Let's find the two ratios that are proportional:
33/18 and 66/26
33/18 is proportional with 66/36, thererefore this is not correct.
9/14 and 45/56
9/14 is proportional with 45/70, this is also incorrect.
18/15 and 24/20
6/5, 12/10, 18/15, 24/20, 30/25 are proportional.
This is the correct answer. However, let's check the last one.
4/6 and 9/12
4/6 and 8/12 are proportional. This is wrong.
