Final answer:
Glycosuria occurs when the transport maximum (Tm) of the renal glucose transport protein is exceeded.
Step-by-step explanation:
Glycosuria occurs when the transport maximum (Tm) of the renal glucose transport protein is exceeded.
Glucose is filtered by the kidneys and then reabsorbed. However, there are a limited number of carrier proteins for glucose in the kidneys. When the amount of glucose in the blood exceeds the capacity of these carrier proteins, the excess glucose is not transported and is excreted in the urine, resulting in glycosuria.
Therefore, the correct answer is B. transport maximum which highlights this renal protein's capacity threshold, pivotal in regulating glucose levels and understanding renal glucose handling intricacies.