I think its D.

Here is the explanation:

x = y *q + r where x,y,q, and r are integers.

Case I:

x/y = 15.15 i.e x = 15y + 0.15 y

So 0.15 y = 60 i.e y = 400 (an integer).

Its possible.
Case II:

x/y = 18.16 i.e x = 18y + 0.16 y

So 0.16 y = 60 i.e y = 375 (an integer).

Its possible.
Case III:

x/y = 17.17 i.e x = 17y + 0.17y

So 0.17y = 60 i.e y = 100/17 (Not integer).

This is not possible. _________________

SAID BUSINESS SCHOOL, OXFORD - MBA CLASS OF 2008