Should I use 2732*2048 or 2048*1536 to develop for 12.9 iPad Pro?

Hello, there!

When I check up spec of 12.9 iPad Pro , I found the resolution of it is 2732* 2048.

I’m confused which on to use in CGSize. 2048, 1536 or 2732, 2048?

I want my game optimized for 12.9 iPad Pro.

Also, Should I use 2732, 2048 as recourse image?

Thanks!