------------------------------- 0 ------ 1/8 --- 1/5 ----1/4--------

if you see the number line above -- as denominators in the fractions increases - the number moves towards 0 (gets closer to 0). So 1/64 is the closest fraction to 0 increasing towards 1/32 which is below (or less than) 1/4 in the above number line.

From this start looking at answers: 3 should be the answer.

I am sure there is a better way to do this problem, but here is how I tackled it…
S=1/32 + 1/33 + ... +1/64, S is in which of the following range?
I quickly found the upper and lower bounds…

Upper bound is 33 * 1/32, which is just over 1
Lower bound is 33 * 1/64, which is just over 0.5
Hence S is between 0.5 and 1 (Answer #2)

You could also take 33/48 (48 is the average denominator), this gives you roughly .69, which is between 0.5 and 1

The OA is 0.5 to 1....