The position vector of a particle in a circular motion about the origin sweeps out equal area in equal time.

(A.) & (C.) The position vector is in a circular motion about the origin, i.e. its direction changes at every instant and direction dependent vectors like velocity and acceleration change along with it.

(B.) The speed is independent of the direction if motion, therefore it will remain constant throughout.

(D.) The tangential acceleration is zero at all points on the circular path, therefore it is also a constant.