Which of the following types of life rafts is equipped with boarding ramps?

The correct answer is the 20-man life raft, as it is typically designed to accommodate larger groups and includes features that facilitate easier entry, such as boarding ramps. These boarding ramps are particularly useful in emergency situations where rapid access to the raft is necessary, as they allow individuals to get on the raft quickly and safely from the water, reducing the risk of injuries or difficulties during boarding. Rafts designed for smaller capacities may not have such features, as they are generally intended for fewer occupants and therefore may prioritize other design elements over the inclusion of boarding ramps.

In contrast, while the 4-man, 10-man, and 40-man life rafts may have specific features suited to their respective capacities, the inclusion of ramps is more characteristic of the 20-man life raft, which balances size and safety features aimed at collective rescue in a more significant emergency scenario.