What appearance do erythrocytes have when they are crenated?

When erythrocytes are described as crenated, they present a shrunken appearance with ruffled or scalloped edges. This occurs due to the loss of water from the cells, often as a result of exposure to hypertonic solutions, which causes the cells to shrink. The ruffled edges give them a distinctive appearance that differentiates them from healthy, biconcave red blood cells, which typically have smooth, rounded edges. Thus, the correct answer reflects the characteristic shrunken nature and darker coloration of the crenated cells, as compared to their normal state.