Which of the following must be carried out in order to manually launch an inflatable life raft not designed for float-free operation?

Correct Answer: Option D — Depress the hydrostatic release button.

Manually launching a life raft not equipped for float-free operation requires the operator to depress the hydrostatic release unit or manually release the slip hook. This action disengages the securing mechanism, allowing the raft container to be pushed overboard for inflation via the painter line.