Which Grade CRS can survive in my tank?

Hi all,
Just before I get my hands on some better grades CRS, would like to ask for your experienced opinions. My tank temp ranges from 22 - 28 degree max throughout the day. It is on air con room at night and in the day the room does not have any sunlight coming in thus the maximum tempreture is about 28 in the late afternoon.

Currently having C grades in my tank, what grade is the max I can put in my tank at such tempreture? Please advise.