The correct answer is: C. 85 and 75.
Crawler-mounted cranes have a higher rated load than pneumatic tyre-mounted machines at a specified radius. This is because crawler-mounted cranes have a lower center of gravity, which makes them more stable. Pneumatic tyre-mounted machines have a higher center of gravity, which makes them more susceptible to tipping.
The rated load of a lifting crane is the maximum load that the crane can safely lift at a specified radius. The radius is the distance from the center of the crane’s load hook to the center of the crane’s base. The rated load of a crane is typically specified in a table, which shows the maximum load that can be lifted at different radii.
The rated load of a crane is affected by a number of factors, including the type of crane, the length of the crane’s boom, the weight of the crane’s counterweight, and the wind speed. The rated load of a crane should always be consulted before lifting any load.