choose the sentence that fits best in the blank.

in tennessee, there is a large, beautiful lake inside a giant cave. years ago people named it the "lost sea." in the 1800s, native americans and southern soldiers would hide in the cave by the lake. this cave was once even used as a dance hall.

a. tennessee also has beautiful mountains.

b. caves can contain stalactites or stalagmites.

c. lakes are usually filled with fresh water.

d. it is the world's largest underground lake.