Critical Reasoning

1. French divers recently found a large cave along the
coast of the Mediterranean Sea. The cave is accessible
only through an underwater tunnel. The interior of
cave is completely filled with seawater and contains
numerous large stalagmites, which are stony pillars
that form when drops of water fall repeatedly on a
single spot on a cave floor, leaving behind mineral
deposits that accumulate over time.
The information above most strongly supports
which one of the following?
(A) The Mediterranean Sea was at a higher level
the past than it is now.
(B) The water level within the cave is higher now
than it once was.
(C) The French divers were the first people who knew
that the tunnel leading to the cave existed.
(D) There was once an entrance to the cave besides
the underwater tunnel.
(E) Seawater in the Mediterranean has a lower
mineral content now than it had when the
stalagmites were being formed.


Would anyone explain how the answer is B.If this is already discussed please let me know the link