4.1 Discuss the main differences between forward and futures contracts. 4.2 Consider the following two portfolios: Portfolio A: one European call option plus a zero-coupon bond that provides a payoff of K at time T; Portfolio B: one European put option plus one share of non-dividend-paying stock. Assuming that the call and put options have the same strike price K and the same time to maturity T, analyse the relationship between the values of underlying stock price at time T and the values of portfolio A and portfolio B. 4.3 Based on the analysis in question 4.2, design an option strategy that replicates the payoff of a forward contract.