Which sentence is punctuated correctly? 

A.Under a microscope; the organisms look a bit like ruffled tennis balls they have armored plates that fit together to make a round shape.
B.When the water is disturbed; the organisms respond by glowing this makes swimmers look like floating beams of blue light.
C.There is a bay in Puerto Rico that seems to light up at night; the light comes from tiny organisms in the water.
D.The luminescence attracts visitors from around the world people are curious to see; this beautiful otherworldly sight.