Final answer:
Pseudocasts in urine microscopy are often caused by amorphous urates, which are crystalline substances that can mimic the appearance of cellular casts.
Step-by-step explanation:
Pseudocasts in urine microscopy are often artifacts rather than true cellular elements and can be caused by a variety of substances. The option C. Amorphous urates refers to the crystalline substances found commonly in urine that can sometimes mimic the appearance of cellular casts when viewed under a microscope. These pseudocasts are not indicative of kidney damage as cellular casts would be, but instead result from the precipitation of urate crystals as the urine cools after collection. Therefore, pseudocasts are not related to a dirty cover glass or slide, bacterial contamination, or mucus in the urine, but are more closely associated with amorphous urates.