Great question!!

Given:
QUANTITY A: 33 1/3% of a
QUANTITY B: 25% of b

Since 33 1/3% = 1/3 and 25% = 1/4, we can rewrite the quantities as follows:
QUANTITY A: (1/3)a
QUANTITY B: (1/4)b

To eliminate the fractions, let's multiply both quantities by 12 to get:
QUANTITY A: 4a
QUANTITY B: 3b

Divide both quantities by 3 to get:
QUANTITY A: 4a/3
QUANTITY B: b

Since a is positive, we can safely divide both quantities by a to get:
QUANTITY A: 4/3
QUANTITY B: b/a

Since a > 3 and since b < 4, we know that b/a < 4/3

Answer: A