Ahomeowner and a builder entered into a written contract to build a sauna in a spare room in the homeowner's home at a cost of $3,000. the contract contained a clause stating that the builder will not begin construction without prior approval of the plans by the homeowner's certified public accountant. the builder submitted his designs to both the homeowner and the accountant. the homeowner liked the plans, but the accountant did not and withheld his approval. the builder asked the homeowner whether she wanted him to submit new designs. the homeowner told the builder orally, "no! your designs are great! my accountant is crazy! you go right ahead and construct the sauna." the builder constructed the sauna. the homeowner now refuses to pay the builder, citing the clause requiring approval by the accountant. if the builder sues the homeowner, the builder will recover: a. the full contract price, because the accountant's approval was not a condition precedent for the contract to take effect. b. the full contract price, because once the builder began building the sauna after speaking to the homeowner, the homeowner did nothing to stop the builder. c. the reasonable value of the builder's services and materials, because otherwise the homeowner would be unjustly enriched. d. nothing, because the homeowner's oral statement will be excluded by the parol evidence rule.