$16.$ If at expiration, the underlying stock price is $$50$ per share, what is the total intrinsic value per share of long a call with an exercise price of $$30$ and

short a call with an exercise price of $$40?$

A$)-$$$10$

B$)$ $$0$

C$)$ $$10$

D$)$ $$20$

E$)$ $$50$