What happens during the regulation action of a Zener diode?

Choose the correct option:

To reduce the ripples in rectifier circuit with capacitor filter:

(a) R_L should be increased
(b) input frequency should be decreased
(c) input frequency should be increased
(d) capacitors with high capacitance should be used

1. (a, c)

2. (b, d)

3. (a, c, d)

4. (b, c, d)