Answer:
A, C, D
Step-by-step explanation:
You want the angles in the list that have π/3 as the reference angle.
Reference angle
The reference angle is the smallest angle between the angle's terminal side and the x-axis. The cosine and sine of the reference angle have the same magnitude of the cosine and sine of the angle in question.
The attached table shows that 7π/3, 2π/3, and 19π/3 have the same reference angle: π/3.
