A ball tied to the end of the string swings in a vertical circle under the influence of gravity.
a. When the string makes an angle 90∘ with the vertical, the tangential acceleration is zero and radial acceleration is somewhere between minimum and maximum
b. When the string makes an angle 90∘ with the vertical, the tangential acceleration is maximum and radial acceleration is somewhere between maximum and minimum
c. At no place in circular motion, tangential acceleration is equal to radial acceleration
d. When radial acceleration has its maximum value, the tangential acceleration is zero