MM create a pattern, you and many others follow it, then they pull a switch-a-roo and take everyone to the cleaner.
You can close your position any time and get the gain like your broker told you. I have never let my option expire, so i can't tell you personally what happen on expiration.
execute your call option when you are in the money, but make sure you have enough cash to buy them shares. Then sell your shares.
This is how wall street makes money. The nellies can cry all the want.
All the major tech stocks are moving up, even Alibaba. Someone is gonna be left holding the bag after this is done.