Cytoplasm often stains poorly because its lipid content is removed by the organic solvents used in the clearing step in routine histological preparations. This problem is most likely to occur with cytoplasmic regions rich in which of the following organelles?
A. Free polysomes.
B. Mitochondria.
C. Lysosomes.
D. Smooth endoplasmic reticulum.
E. Rough endoplasmic reticulum.