The correct option is C The temperature decreases and pressure increases
The Southwest monsoon starts retreating in the first week of September from Pakistan border in Northwest India. Thus, these winds withdraw earlier from the regions where they reach the last. The retreat of these winds takes place due to weakening of low pressure area over the northwestern parts. This happens due to low temperatures caused by apparent shift of the sun towards the equator and also owing to the widespread rains bringing down temperatures perceptibly. Consequently, the air pressure starts decreasing. Such changes in the patterns of atmospheric pressure causes Southwest monsoons to withdraw. Hence, this period is known as the season of retreating Southwest monsoons. By the end of October, these winds retreat from most of northern India because of low temperature and low pressure.