Answer:
Option C - All real numbers
Explanation:
Given : Function

To find : The domain of given function ?
Solution :
Domain is defined as the set of values for which function is defined.
We have given the function,

We know, for any value of
the function
is defined.
Which means the set of all real numbers defined the given function i.e.

Therefore, Option C is correct.
The domain of
is all real numbers.