Build-It Construction LLC Agrees to Build a Warehouse for Corporate

Build-It Construction LLC agrees to build a warehouse for Corporate Storage Inc. According to the terms of the deal, Corporate does not have to pay Build-It if the warehouse is not built. Their respective promises are

A) conditioned on the occurrence of an event.
B) conditioned on the nonoccurrence of an event.
C) conditioned on Build-It's performance.
D) not conditioned.