Choose the best answer: "If you pass your test, I'll buy you a car", he said.

a. He said that If I pass my test, he'll buy me a car.

b. He said that If you passed your test, he would buy you a car.

c. He said that If I passed my test, he would buy me a car.

d. He said that If I had pass my test, he would have bought me a car.