Mitochondria - Within eukaryotic cells, mitochondria function somewhat like batteries, because they convert energy from one form to another: food nutrients to ATP.
Alvin was a deep sea vehicle which was used to explore the depths of the ocean. It sunk but was recovered and recommissioned in 1973 after which it discovered black smokers, a special type of hydrothermal vent which produces super heated water with a highly acidic pH. Thus, the answer is B.