My POST can’t count

You have just installed a new motherboard, but the system will not POST. When you check the motherboard power connection with a multimeter, you find that the 12 volt rail is showing zero volts. Which of these would be the most likely cause of this issue?

A) The new motherboard is faulty

B) The building power receptacle is faulty

C) The power supply is faulty

D) The AC power cable is faulty

E) You computer is so efficient that it only needs air and water to operate