If the underlying stock price is $67 and you are long a one year call option with a strike of $68 and you are short a one year call option with a strike of $72 and you hold both of these position via the same broker.

Given your two positions will you need to post margin? And why? (the why is worth half of the value of the problem)

(when answering please say "yes" or "no" and then explain why)