Part 1:
-Vayan al banco, nice, not commanding. "Y'all go to the bank = Vayan al banco"
-Van al banco is more of asking a question. "Are y'all going to the bank? = ¿Van al banco?"
-Vaya al banco is commanding. "Go to the bank. = Vaya al banco"
-Vais al banco is not proper Spanish at all.
So the answer would be A) Vayan al banco.
Part 2:
Malo is bad, did you mean Enojado, which means mad? We'll go with Malo.
-No es malo is more of a question. "You're not mad? = ¿No es malo?"
-Sean no malo, not, not, not proper Spanish.
-No sea malo, is a question, BUT it is asking not to be mad. "Don't be mad = No sea malo."
-No son malo, this is a statement. "They're not mad = No son malo"
Therefore, the answer would be C) No sea malo.
Hope this helps!~