The correct answer is D) No stowage container for immersion suits may be capable of being locked. This is correct because the regulations for immersion suits specify that the stowage containers must be readily accessible and not capable of being locked. This ensures that the suits can be quickly retrieved in an emergency situation. The other answer choices are incorrect - A) is too restrictive, B) is a good practice but not a requirement, and C) is not entirely accurate as some small repairs may be permissible for immersion suits.