The body is made up of many different cell types, from small circular red blood cells to the elongated smooth muscle cells 20X its size. Why is there such variation in size and shape?

A)Different cell sizes are due to nutritional differences.
B)Different variations in size and shape allow differentiated cell types to perform unique functions.
C)Variations in cell shape and size are due to chromosomal differences between cells.
D)Cell size and shape does not vary among cell types.