A project manager purchases 3,500 widgets for his project. The widgets are delivered on time, but there are many defects in the paint that is on the surface of the widgets. The project manager returns the parts to the vendor for repair and rework. The vendor complains that the paint job quality was not specified in the contract and it is not his responsibility to repair the parts. It is likely that the parts will be repaired by the vendor because of:

a. Expressed warranty.

b. Implied warranty.

c. Past business practices.

d. Threat of legal action by the project team.