s the amount of rain in City Upper B during Aprilamount of rain in City B during April a discrete random variable, a continuous random variable, or not a random variable?

It represents continuous random variable

A continuous random variable is a random variable where the data can take infinitely many values. For example, a random variable measuring the time taken for something to be done is continuous since there are an infinite number of possible times that can be taken.

For example, in this problem we are interested in rain during April, it means we are interested in time. So, a time is represented by continuous random variable.