Amit solved the equation 5/12 = -x/420 for x using the steps shown below. What is Amit's error?
5/12 = -x/420 5/12(420) = -x/420(420) x = 175
A: Amit should have multiplied both sides by 5/12 B: Amit should have multiplied both sides by 12/5 C: The product of 5/12 and 420 is not equal to 175 D: The product of 5/12 and -420 should have been the value of x