C is correct, x6
This is because when a smaller number is put above (as an exponent of another), you would read it as (the base number) to the power of (the exponent).
A is saying 6 TIMES some number
B is saying some number PLUS 6
C is actually saying some number TO THE POWER OF 6
D is close but not quite right, instead of x to the power of 6, it is 6 to the power of x which is not what is being asked of us.
