Answer:
C. 47°
Explanation:
The angle between the terminal ray of 227° and the nearest x-axis (the negative x-axis) is ...
227° -180° = 47°
The reference angle is 47°.
_____
In mathematical terms the reference angle is the minimum of the angle modulo 180° and the supplement of that angle.
227° modulo 180° = 47°
180° -47° = 133° . . . . supplement of 47°
min(47°, 133°) = 47° . . . the reference angle