A simple pendulum executes always:

The correct answer is: Only oscillatory motion

1. A simple pendulum executes an oscillatory motion.
2. The to and fro motion of an object about its mean position is called oscillatory motion.
3. Movement of a simple pendulum, movement of a swing, movement of the needle in a sewing machine are the examples of oscillatory motion.

Hence, a simple pendulum executes oscillatory motion.
The to and fro motion of a simple pendulum is an example of a periodic
Hence Both a and b