Final answer:
Ladders have five workload ratings, as categorized by the American National Standards Institute (ANSI): Type IAA, Type IA, Type I, Type II, and Type III. Each type corresponds to specific maximum weight capacities, ensuring the safe use of ladders.
Step-by-step explanation:
Ladders are classified according to their Duty Rating, which indicates the maximum weight capacity that a ladder can safely support. The American National Standards Institute (ANSI) has defined five main categories of ladder Duty Ratings:
- Type IAA (Extra Heavy Duty) - 375 lbs
- Type IA (Extra Heavy Duty) - 300 lbs
- Type I (Heavy Duty) - 250 lbs
- Type II (Medium Duty) - 225 lbs
- Type III (Light Duty) - 200 lbs
These ratings ensure that ladders are used within their safe working limits. Therefore, the options 'a' and 'b' from the question do not correctly describe the number of workload ratings for ladders. There are actually five workload ratings for ladders, not just one or two.