John Operates a Small Repair Business and Is in Desperate

John operates a small repair business and is in desperate need of a certain type of building material. He obtains the material from a large corporation, but is charged a grossly unreasonable price and is forced to buy other material he does not need. In view of the buyer's unequal bargaining power and unreasonable terms of the contract, this may be a case of:

A) in pari delicto .
B) partial illegality.
C) substantive unconscionability.
D) procedural unconscionability.