B is your answer all of the above
Because the bouyancy of something also depends on it's weight (mass).
When you unload a ship, less gravity is applied to it (gravity pulls things down), so that is why it rises.
Answer:
B
Hope it helped,
BioTeacher101
This procedure is called a vacuum extraction or vacuum assisted delivery. In vacuum assisted delivery, the healthcare practitioner uses a vacuum device with a cup with a handle and a vacuum pump to expedite the delivery of the baby. The vacuum assisted delivery is indicated in mothers undergoing labor for a longer time than normal; with inadequate contractions and failure of cervical dilatation to progress.