Kip Sells an Apartment Building to Lacy with a Promise

Multiple Choice

Kip sells an apartment building to Lacy with a promise to repair the roof, which violates the local housing code, within six months. One year later, Kip sends Milo, a carpenter, to fix the roof. Lacy orders Milo to leave and refuses to make further payments to Kip, who files a suit against Lacy.
-Refer to Fact Pattern 15-1.Lacy's refusal to make further payments is most likely

A) a material breach.
B) complete performance.
C) excused by Kip's failure to fix the roof.
D) substantial,but not complete,performance.