Final answer:
Substances that are not subject to filtration, reabsorption, or secretion through the kidney's nephron processes would stay in the blood and be found in the renal vein.
Step-by-step explanation:
If a substance is neither filtered, reabsorbed, nor secreted, you would expect to find it in b) Blood in the renal vein.
The kidneys filter blood through a process that involves glomerular filtration, tubular reabsorption, and tubular secretion. In the filtrate modification process, if a substance is not filtered, it stays in the blood and does not enter Bowman's capsule. Since the substance is not reabsorbed or secreted, it remains in the blood as it passes through the nephron and ends up in the renal vein.
During this process, blood enters the kidney through the renal artery and passes through the glomerulus in the nephron, where filtration occurs. Filtered material proceeds through the renal tubule, but since our substance of interest is neither filtered out to form the initial glomerular filtrate nor subject to reabsorption or secretion, it remains in the blood, which is subsequently collected in the renal vein.