Answer:
Option C
Explanation:
A linear function is one that is written as y = f(x) = mx + b
It thus cannot have square roots or exponents
A) A does not follow the format, as "y" is not isolated onto one side.
B) B does not follow the format, as there is a square root
C) C follows the format, because the "y" is on its own side and there are no exponents
D) D does not follow the format because x is being squared.
The only option that follows the format y = mx + b is option C, so that is the answer.