To everyone asking: I do not know if it is intended, or a bug but as of right now these are the steps required to unlock the 3rd option:
#1 - in Ch2, when throwing the guy off the boat, you *MUST* choose "I got your back, Sis".
#2 - in Ch3, when given two options "Speak for yourself" or "Maybe it doesn't have to be that way" you *MUST* choose "Speak for yourself"
Those 2 options unlock the 3rd one in the overboard scene.
Note: I didn't parse the script quite enough, so I don't know if those required options themselves have requirements, but you must choose both in order to get the 3rd option.
It seems like a weird, contradictory combo of options so like I said, idk if it's a bug or intended, but thats how you unlock it as of right now.