Final answer:
The portion of the renal tubule that reenters the cortex and has cuboidal epithelium without microvilli is the Distal Convoluted Tubule (DCT).
Step-by-step explanation:
The student's question pertains to the renal (uriniferous) tubule and specifically to a portion that begins shortly after the ascending limb reenters the cortex, which is characterized by cuboidal epithelium without microvilli. Based on this description, the correct answer is d. Distal Convoluted Tubule (DCT). This can be deduced because the ascending loop of the nephron loop or Loop of Henle, which reenters the cortex after its hairpin turn and is lined by simple cuboidal epithelium without microvilli, leads to the formation of hypoosmotic filtrate as it approaches the DCT. The DCT is also lined with simple cuboidal epithelium but lacks the brush border that is characteristic of the PCT, distinguishing the two.