Suppose Wing needs a baby sitter so that he can travel to his sister's wedding. Wing values baby sitting for the weekend at $350. Mary is willing to baby sit for Wing so long as she receives at least $300. Wing and Mary agree on a price of $325. Suppose the government imposes a tax of $60 on baby sitting. The tax has made Wing and Mary worse off by a total of

a) 25

b) 0

c) 50

d) 60