Dynamic SQL select query

Below is the output set I want from an SP. I will have count as input parameter to the  SP
so If count in 3 and I want the result to be c1, c2, c3, c4, c5,c6,c7,c8,c9
If the Count is 2, then c1,c2,c3, c4

Output of SP:
 
(OP)            C1            C2            C3           C4            C5            C6    C7          C8            C9

I know we can do like below, how do I do it dynamically?

SELECT '(OP)',           ' C1 ',   'C2', 'C3','C4','C5','C6', 'C7','C8',       'C9'