Highlight all the cells in column C that you want this to apply to,
with C2 (say) as the active cell. Then Format | Conditional Formatting
and choose Formula Is and then this formula:

=OR($C2="FLAT",$C2 ="2FS",$C2 ="3FCH")

select your format then OK your way out. Excel will automatically
adjust those cell references to C3, C4, C5 etc on different rows.

Hope this helps.

Pete