It is 2 that what i got and i think i got it write if not delete
For example you have the 52, and you have the 24, you look for a number that can go into both that is the largest possible for my example it would be 4 since no number greater can go into both, while 2 would be a option it would not be the greatest.
X=tax
240+x
that would be your answer i believe
Its d, like the person above be said