Which of the following is a continuous random variable? a) the number of employees in an office b) the salaries of employees in an office c) the number of printers in an office d) the number of phone calls made daily from an office

D. the number of phone calls.

One day there could be 80 phone calls and the next there could be 2. It is continuously random.

D. The number of phone calls made daily from an office

Explanation:
A continuous random variable is defined as a variable where the data can have an infinite number of possibilities.

Let's check the given options:
1- Option A:
The number of employees in an office is fixed. It will not change from one day to another. Therefore, the variable does not have infinite possibilities
> This option is incorrect

2- Option B:
The salaries of employees in an office are fixed. They will not change from one day to another. Therefore, the variable does not have infinite possibilities
> This option is incorrect

3- Option C:
The number of printers in an office is fixed. It will not change from one day to another. Therefore, the variable does not have infinite possibilities
> This option is incorrect

4- Option D:
The number of phone calls made daily from an office is not fixed. They could be any number and can change daily. Therefore, the variable has infinite possibilities
> This option is correct

Hope this helps :)