Let the first-order partial derivative of the option price with respect to the underlying price be Delta. Show that for a pair of call and put options with the same strike price, the same term, and the same underlying

a ) The Delta of the call option minus the Delta of the put option is constant at 1.

b) The implied volatility change has exactly the same effect on the value of the call option and the put option.

( SHORT ANSWER TO ALL STEPS)