Answer: d. (if a polygon has congruent angles, then it is regular)
Explanation:
Converses follow the format of "if q, then p" (while the original conditional is "if p, then q")
Just because there are clouds does not mean its raining (cloudy days)
just because it has four equal sides does not make it a square (rhombi have four equal sides but are not squares)
just because you cannot see the sun does not mean it is not daytime (solar eclipses)
if a polygon is regular, it must have congruent angles