Given:
Quantity A: \(\frac{a^2b}{cd^2} \times \frac{d^3}{abc}=\frac{a^2bd^3}{abc^2d^2}=\frac{ad}{c^2}\)

Quantity B: \(\frac{d^2}{bc} \times \frac{ab^2}{bd}=\frac{ab^2d^2}{b^2cd}=\frac{ad}{c}\)

From here, we can quickly see the answer is D by testing some possible values.

case i: a = c = d = 1
We get:
Quantity A: \(\frac{(1)(1)}{1^2}=1\)

Quantity B: \(\frac{(1)(1)}{1}=1\)
In this case, the quantities are equal


case ii: a = d = 1, and c = 2
We get:
Quantity A: \(\frac{(1)(1)}{2^2}=\frac{1}{4}\)

Quantity B: \(\frac{(1)(1)}{2}=\frac{1}{2}\)
In this case, Quantity B is greater

Answer: D

Cheers,
Brent