How do I get Origin to open in Firefox instead of Google Chrome?

Chrome seems to use more system memory faster on my desktop computer.  I recently bought Sims 4 (CD), and prefer that  the game and Origin opens in Firefox which I always use b/c it ties up fewer resources.  I could not find anything in the Origin Settings to switch to Firefox, only that I could play offline.

I thought of deleting Google Chrome altogether, but worry - and am just guessing - that when I try to play my TS4 game again, this time an Origin account will try to open in IE, which I don't use or like either, AND that Origin will ask me to re-register, but consider this as me playing my game on a 2nd computer.  If so, that's a concern b/c you only get two computers to use for your game when you want to play offline, and when I am ready to buy another computer, I won't be able to play my game offline on it. 

So how do I reconfigure Origin to open in Firefox without deleting Chrome? Thanks!