As the particle is in circular motion, the direction of its velocity changes continuously and so does the total acceleration. So the option A is not correct.
To cover equal area in equal time, particle will have to move with constant speed because if it increases its speed, area swept will be larger than the area swept in the previous time period. So the option B is right.
Since the speed is constant, its tangential acceleration is equal to zero (a constant). So the option 'D' is also right. Total acceleration, however, does not remain constant.