I understand that Quantity B will always be bigger due to its non-terminating nature.
What if x and y are equal zero though?
Then both have the same number of digits after the decimal point. So why can’t it be D?
0 is a multiple of 7.
Not sure if I get your point? 21 is also a multiple of 0?
Correct - which means that the “x = 0, y = 0” case cannot work because the question says that y is not a multiple of 7, which 0 is.