QualMart hires Builders, Inc., to construct a new warehouse. The builders risk insurance requirements for this contract stipulate that coverage must remain in place until a specific event occurs. Which is not a common "event" that could signal the end of the required coverage period? Oa. QualMart makes its final payment to Builders, Inc. Ob. QualMart is the only remaining insured with an insurable interest in the property. oc. Builders, Inc., has removed all of its tools and equipment from the site.