The correct answer is (c) 32.5.
The average age of employees below 40 years of age is calculated by taking the sum of the ages of all employees below 40 years of age and dividing by the number of employees below 40 years of age. The sum of the ages of all employees below 40 years of age is 40 + 60 + 55 = 155. The number of employees below 40 years of age is 40 + 60 = 100. Therefore, the average age of employees below 40 years of age is 155 / 100 = 32.5.
Option (a) is incorrect because it is the average age of all employees, not just employees below 40 years of age. Option (b) is incorrect because it is the average age of employees in the 30-40 age group. Option (d) is incorrect because it is the average age of employees in the 40-50 age group.