Two aldopentoses A and B give the same osazone derivation. A is oxidised to an optically active aldaric acid by dilute nitric acid. Ruff degradation of B gave a tetrose which was similarly oxidised to an optically active aldaric acid. Assign the structure of A and B from the following list:
![582542.PNG](https://search-static.byjusweb.com/question-images/toppr_invalid/questions/582542.PNG)