4. a) You have bought a Call spread with a bought strike of 40 and a sold strike of 50. Say whether the following are always positive, always negative, or does it depend on where the stock price is. 1.

Answer the question for the following: Delta, Gamma, Vega, and Theta. No need for explanations.

b) What happens to the Gamma of an at-the-money call option as it approaches expiration?