Answer:
A good identifier for a variable that will be used to hold an employee’s phone number is:
a. EmployeePhoneNumber
Explanation:
An identifier is a string that uniquely identifies or names the entity or an object. The object or entity may be a constant, variable, structure, function, etc. Identifiers can be formed from uppercase and lowercase letters, digits, and underscores. Meaningful identifiers mostly favor the use of long descriptive names like EmployeePhoneNumber. However, the other options can still be used.