In an office, the distribution of work hours is as shown in the following table: No. of Staff Members | No. of hours worked 5 | 0 – 19 12 | 20 – 24 25 | 25 – 29 40 | 30 – 34 15 | 35 – 39 8 | 40 – 45 Consider the following inferences drawn from the table: I. The average number of hours worked by a staff member is about 30. II. The percentage of those who worked 35 or more hours is less than 25. III. At least 5 staff members worked more than 44 hours. Which of these inferences is/are valid?

1. (a)I alone
2. (b)II alone
3. (c)I and II
4. (d)I, II and III