CRU 240hz question

Hello,

I got a question. I have a benq 2546 240hz monitor but my gpu dont show the 1280x960 resolution.

Whats is better? Lcd standar, lcd native or lcd reduced for 240hz and good clock?

LCD standar: 240hz / 259.201 kHz / 373.25 mhz
LCD native: 240hz / 237.125 kHz / 341.46 mhz
LCD reduced 240hz / 234.005 hHz / 320.12 mhz

Display scaling or gpu scaling?
Thanks!