You Are Faced with a Linear Programming Objective Function Of

You are faced with a linear programming objective function of: Max P = $20X + $30Y
And constraints of:
3X + 4Y = 24 (Constraint A)
5X - Y = 18 (Constraint B)
You discover that the shadow price for Constraint A is 7.5 and the shadow price for Constraint B is 0. Which of these statements is True?

A) You can change quantities of X and Y at no cost for Constraint B.
B) For every additional unit of the objective function you create, you lose 0 units of B.
C) For every additional unit of the objective function you create, the price of A rises by $7.50.
D) The most you would want to pay for an additional unit of A would be $7.50.