Answer:
B) had our house painted
Step-by-step explanation:
A) had our house paint, part of it is correct, but "paint" is a noun, and its present form is painting.
C) had painted, that one is missing the subject of the sentence, "We had painted last month"
D) had painted our house, this one is tricky because this is technically correct in a casual conversation but B makes more sense.
B)
Has a Subject: The house, and it also uses past phrases in the proper order, had, and painted.
Hope it helped!