If Drug a Has an ED₅₀ Value of 12

Multiple Choice

If drug A has an ED₅₀ value of 12.0 mg/kg, and drug B has an ED₅₀ value of 4.0 mg/kg, what can we say about the potencies of these drugs?

A) Drug A is three times more potent than drug B.
B) Drug A is eight times more potent than drug B.
C) Drug B is three times more potent than drug A.
D) Drug B is eight times more potent than drug A.