hi.
to start this exercise, let's remember some definitions about the alternatives:
a. ray
distance between the center of the circle and a point on its circumference (one straight line)
b. vertex
is a point where two edges meet
c. angle
is formed by two semi-straights that come from the same origin
d. opposite rays
is the same definition of radius, only now it considers two rays: one and its opposite. joining a radius to its opposite, we get a straight line.
