(a) What is the Black-Scholes Partial Differential Equation for the price f(t,St) at time t of a European derivative security on a stock with price St? Specify the meaning of the terms or symbols in the equation.

(b) Note that the Black-Scholes Partial Differential Equation does not specify whether the derivative is a call option, a put option, or some other derivative. How do you incorporate the derivative payoff when using Black-Scholes PDE to price a derivative?