Choice A is the same as y = 0 because 0x turns into 0. Multiplying 0 with any number always leads to 0.
Similarly, choice D is the same as y = 0 as well. Dividing 0 over any nonzero value leads to 0. Note the key term "nonzero" here. We cannot have 0 in the denominator. So x = 0 is not allowed for choice D.
So for any nonzero x, we have 0x and 0/x result in the same thing.
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Extra info:
Choice B can be ruled out because something like x = 2 leads to y = 2.
Choice C is ruled out because we can never have 0 in the denominator.
