How often is a drill on the use of the line throwing appliance required to be held on a mobile offshore drilling unit?

Correct Answer: Option A — Once every three months

46 CFR 109.213 stipulates that drills involving the use of the line-throwing appliance must be conducted at least once every three months. This frequency ensures that designated crew members remain proficient in the assembly and operation of the device, which is critical for establishing communication or rescue lines.