The correct answer is B) feeler gage. A feeler gage is the correct tool to detect misalignment between the drive shaft and propeller shaft flanges. Feeler gages allow you to precisely measure the gap between the two flanges, which indicates if they are properly aligned. This is a common technique used in the maintenance and inspection of marine propulsion systems. The other options are not as suitable for this task. An inside micrometer (A) would not be able to span the gap between the flanges. A trammel (C) is used for larger measurement tasks, not the precise gap checking required here. A sighting device (D) would not provide the quantitative measurement needed to assess the alignment.