Firms a Must Decide Whether or Not to Introduce a New

Firms A must decide whether or not to introduce a new product.If Firm A introduces a new product, Firm B must decide whether or not to clone the product.The payoff structure of the game is depicted in the above tree diagram.The sub-game perfect Nash equilibrium to this game is

A) Firm A plays "Introduce"; Firm B plays "Clone" if Firm A plays "Introduce".
B) Firm A plays "Do Not Introduce"; Firm B plays "Clone" if Firm A plays "Introduce".
C) Firm A plays "Introduce"; Firm B plays "Do Not Clone" if Firm A plays "Introduce".
D) Firm A plays "Do Not Introduce"; Firm B plays "Do Not Clone" if Firm A plays "Introduce".