Schizophrenia vs a puppy

[Mary Jay]

Hi guys,
I need your advice:
I have a small rental and having a hard time to decide who to pick:
1) First tenant has schizophrenia but his sister always pays on time (the reason I know it is because he is renting a basement from my handyman and he wants to get out of the basement and rent his a house). He does not work, has social security. He wants a long term. His sister may cosign the lease, or may not.

2) A girl who has a one year old mix huskey/rotweiler dog . She wants only 1 year lease (she is a student, and works full time)
Everything else is the same , same amount of income, etc..
Thank you!