The answers would be "abuelo" and "abuela".
The question, translated into English, reads:
—Are they your grandparents?
—Yes, he is my _____ and she is my _____.
As "abuelo" is the term for a masculine grandparent (or "grandpa"), it would go in the first blank, and "abuela", being the feminine equivalent ("grandma"), would go in the second.
