Sarah Is 16 Years Old

Sarah is 16 years old.She left home at age 15;her parents no longer support her.Sarah entered into a contract with Best Groceries for the purchase of $100 of groceries on credit.The groceries consisted of basic,necessary items.However,their reasonable value is only $80.If Sarah discovers that she has been overcharged and refuses to pay,Best Groceries is entitled to collect:

A) nothing.
B) $80.
C) $100.
D) $90.