Loss of things, impossibility of performance in alternative obligation

Article 1204 of the Civil Code applies when the right of choice belongs to the debtor, to wit:

ART. 1204. The creditor shall have a right to indemnity for damages when, through the fault of the debtor, all the things which are alternatively the object of the obligation have been lost, or the compliance of the obligation has become impossible. 

The indemnity shall be fixed taking as a basis the value of the last thing which disappeared, or that of the service which last became impossible.

Damages other than the value of the last thing or service may also be awarded. (1135a)

What happens when the debtor has the right of choice in an alternative obligation and the prestations are lost or become impossible?

If due to a fortuitous event all of the prestations are lost or become impossible, the debtor is released from the obligation. If  all of the prestations are lost or become impossible because of debtor's fault, the creditor shall have a right to indemnity for damages based on the value of the last thing which disappeared or service which become impossible, plus damages other than the value may also be awarded. If due to a fortuitous event, some of the prestations are lost or become impossible, the debtor must perform that which he shall choose from among the remainder. If some of the prestations are lost or become impossible due to debtor's fault, the debtor must perform that which he shall choose from among the remainder, without liability for damages. If only one of the prestation remains, even if it is because of a fortuitous event or debtor's fault, the debtor should perform the remaining prestation.

Moreover, under Article 1205 of the Civil Code, the creditor has the right to choose, to wit:

ART. 1205. When the choice has been expressly given to the creditor, the obligation shall cease to be alternative from the day when the selection has been communicated to the debtor. 

Until then the responsibility of the debtor shall be governed by the following rules:

(1) If one of the things is lost through a fortuitous event, he shall perform the obligation by delivering that which the creditor should choose from among the remainder, or that which remains if only one subsists;

(2) If the loss of one of the things occurs through the fault of the debtor, the creditor may claim any of those subsisting, or the price of that which, through the fault of the former, has disappeared, with a right to damages;

(3) If all the things are lost through the fault of the debtor, the choice by the creditor shall fall upon the price of any one of them, also with indemnity for damages. 

The same rules shall be applied to obligations to do or not to do in case one, some or all of the prestations should become impossible. (1136a)

If due to a fortuitous event all of the prestations are lost or become impossible, the debtor is released from the obligation. If  all of the prestations are lost or become impossible because of debtor's fault, creditor may claim the price/value of any of them, with indemnity for damages. If due to a fortuitous event, some of the prestations are lost or become impossible, debtor must deliver that which he shall choose from among the remainder. If some of the prestations are lost or become impossible due to debtor's fault, the creditor may claim any of those subsisting without a right to damages or price/value of the thing lost, with right to damages. If due to a fortuitous event one of the prestations only remains, the debtor must perform the remaining. If there is only one prestation remaining because of debtor's fault, the creditor may claim the remaining thing without a right to damages or the price/value of the thing lost with right to damages.