Over the centuries, many squid specimens have been found, but it's hard to get an idea of how the squid lives because it typically cruises in the deepest depths of the ocean. We know that the giant squid's main predator is the sperm whale. We know this because bits of giant squid have been found in the stomachs of sperm whales. We also know they feed on deep-sea fish and other squid. We know this because of all the giant squid that have washed ashore.

Which of the following best states the central idea of the bolded paragraph?

Sometimes giant squid wash ashore.
It seems that giant squid have one primary enemy: the sperm whale.
Over the centuries, many squid specimens have been found, but it's hard to get an idea of how the squid lives because it typically cruises in the deepest depths of the ocean.
Although the giant squid is difficult to study because of its dwelling depth, evidence of how it lives is found in interesting places.