Answer:
John can claim 3 dependents.
Step-by-step explanation:
John can claim three dependents. First is for Kevin, who stays with him. Second is Donna, who is John's mother and third Melissa, his stepsister. Morris is John's cousin and he cannot be claimed as a dependent because he doesn't stay with John at his place. A cousin is also not qualified for tax purposes and in case he wants to claimed as a dependent he needs to live with the taxpayer. Kevin in this case stayed with John in 2019. So, he is eligible to be claimed as a dependent.
Thus, total three dependents can be claimed by John.