Answer:
Step-by-step explanation:
<em><u>Let's find out for which angle could </u></em>
<em><u> be the Reference angle.</u></em>
For this exercise it is important to remember the definition of "Reference angle".
A "Reference angle is defined" as the smallest angle that is measure between the terminal side of an angle and the x-axis.
In this case, you have the following Reference angle provided in the exercise:

It is important to know that:
1. If the angle
is in the First Quadrant, then the reference angle and
are equal
2. If the angle
is in the Second Quadrant, then the reference angle is:

3. If the angle
is in the Third Quadrant, then the reference angle is:

4. If the angle
is in the Fourth Quadrant, then the reference angle is:

By definition, the angle
is in the First Quadrant, therefore, you can say that