C) 12/15
2/3 is equivalent to 6/9 because if we multiply the denominator and numerator of 2/3 by 3 then it it’s equal to 6/9 so we know a) and b) are equal. If we multiply both the denominator and numerator of 6/9 by 6 it equals to 36/54 and if we multiply both the denominator and numerator of 18/27 by 2 it equals 36/54 so b) and d) are equal. That leaves c) as the odd man out
