As the temperature is increased, the period of a pendulum:

1. increases as its effective length increases even though its centre of mass still remains at the centre of the bob.
2. decreases as its effective length increases even though its centre of mass still remains at the centre of the bob.
3. increases as its effective length increases due to the shifting of the centre of mass below the centre of the bob.
4. decreases as its effective length remains the same but the centre of mass shifts above the centre of the bob.

(1) Hint: The time period of the bob depends on the effective length of the pendulum.
Step 1: Find the time period of the pendulum.
As the temperature is increased, the length of the pendulum increases. We know that the time period of a pendulum, T =2πLg
              TL
As L increases, the time period also increases.