Answer:

The answer is C.
Step-by-step explanation:
So we have the rational function:

In rational function, the domain is simply all real numbers except for the values when the denominator equals 0. In other words, we need to find the zeros of the denominator. To do this, set the denominator to zero:

Therefore, the domain is all real numbers except for 1/4.
In interval notation, this is:

The left one represents all the values to the left of 1/4.The right represents all the values to the right of 1/4. The union symbol is needed to combine the two. Note that we use parentheses instead of brackets because we do not include the 1/4 nor the infinities.