Which statements are always true about regular polygons? Select all that apply. o A. All sides are congruent. O B. Pairs of sides are parallel. O C. All angles are congruent. O D. All angles measure 90°.

□ B. Pairs of sides are parallel

All sides are congruent:- This is applied to square but not for other polygons like triangle, rectangle etc.All angles are congruent:- It is not always possible that all angles of a polygon are congruent. This can be applied for equilateral triangle, rectangle, square etc.All angles measure 90°:- It is also not true always because the angles of a triangle do not measure 90°.So, Only Option B is the statement that can be applied for all polygons..

21 is the answer the answer is 21