The correct option is
A ![](https://df0b18phdhzpx.cloudfront.net/ckeditor_assets/pictures/1376149/original_96.png)
In the given substrate both aldehyde groups does not have a
α-hydrogen so it undergo cannizzaro reaction in presence of strong base. Also both aldehyde groups are in single substrate. Hence, it is a intramolecular cannizzaro reaction.
In this reaction one aldehyde group get reduced to alcohol and one oxidised to carboxylic acid.
Formed product on acidification form cyclic ester (lactones).
![](https://df0b18phdhzpx.cloudfront.net/ckeditor_assets/pictures/1376158/original_910.png)