Answer:
option A, is the best technique for sampling the ocean floor
Step-by-step explanation:
Ocean coring is a process in which sample of sea floor sediment is taken and studied to understand its composition. it is a common practice during the petroleum production from sea floor and hence is known as ocean sediment coring.
Usually a cylindrical sample is extracted beneath the sea floor by dropping a cylinder through the water. The sedimentary sample collected show the deposition of sediment (variation) with due course of time.
hence , option A is correct