An arbitrager searches for mispricing and finds that a European call option on a BHP has an exercise price of $30, matures in one year and has an implied volatility of 30%. A put option on BHP with the same expiry has an exercise price of $30 and an implied volatility of 33%. a) An arbitrage opportunity exists because Select) b) The arbitrage opportunity open to a trader is to (Select] c) Is the lognormal assumption underlying Black-Scholes necessary for this arbitrate opportunity to work? Select]