The correct answer is B) after you enter the water. The reasoning for this is that the external flotation bladder on an immersion suit is designed to provide additional buoyancy if needed, but it should not be inflated before entering the water. Inflating the bladder before entering the water could cause the suit to float upright and restrict your ability to enter the water safely. The proper procedure is to enter the water first, and then inflate the bladder if you need additional flotation. The other options are incorrect because: A) inflating before entering the water is not the correct procedure, C) waiting an hour to inflate is unnecessary, and D) you should not wait until you notice buoyancy loss, as the bladder should be inflated immediately if needed.