1. PV (option A)
A radius is a line segment that extends from the center of the circle to the exterior.
2. RT (option C)
A tangent is a line that touches the circle at only one point and exists on the outside of the circle.
3. PVU (option A)
A central angle has its vertex at the center of the circle. The two lines which make up the sides of the angle are going to be radii.
Hope this helps!