Assume That Joe Is Willing to Produce a Hamburger for $1

Assume that Joe is willing to produce a hamburger for $1, and Mary is willing to pay $3 for a hamburger. Which of the following is true?

A) Joe and Mary can make a mutually beneficial exchange.
B) Joe and Mary cannot make a mutually beneficial exchange.
C) Joe and Mary will not trade in equilibrium.
D) Joe and Mary will only trade if the equilibrium price is less than $1.