The correct answer is A) To cut off the power when the davits are about 12 inches or more from the track safety stops. The purpose of the limit switch on gravity davits is to automatically cut off the power when the davits are approximately 12 inches or more from the track safety stops. This is a safety feature to prevent the davits from crashing into the stops and potentially causing damage or injury. The limit switch ensures the davits slow down and stop before reaching the end of the track, which is required by Coast Guard regulations for the safe operation of these types of davits. The other options are incorrect because B) would be too late to cut off power, C) is not the primary purpose of the limit switch, and D) is not accurate.