A. Do nothing because you just have water in your ear canal. C. Dive deeper to equalize the pressure in your ears. D. Ascend, end your dive, and seek medical attention because your eardrum has ruptured. These are the classic symptoms of a ruptured eardrum. This can lead to hearing loss if not treated with antibiotic ear drops.
Diving deeper can also worsen the damage.
If you are stranded on the ocean in a life raft you can safely drink the ocean water to maintain hydration. The very high salt content of ocean water would not allow you to maintain hydration. While mountain climbing your friend has difficulty moving his arms and legs and begins hallucinating. You suspect he has swelling of his brain due to the altitude. B. Descend with him as quickly as possible.