Aaron's dad gave him $50 for cutting their grass. Aaron used the money to buy a $9.75 hat and two hamburgers that cost $1.25 each. Aaron also bought a birthday gift for his mom. If Aaron went home with 1/5 of the money his dad gave him, how much did the birthday gift cost? Show Work!
(A) $27.75
(B) $28.75
(C) $37.75
(D) $38.75