An object is attached to a string. It is twirled in a horizontal circle above the ground at a speed according to the image below. A ball is moving on a clockwise circular path. The ball is currently at the top right position of the circle. Point a is above and to the left of the ball. Point b is above and to the right of the ball. Point c is down and to the right of the ball. Point d is down and to the left of the ball and inside the circle near the center. The direction of the force in the string at the object's location shown points toward which letter? A B C D