Correct option (b) potassium urate
Explanation
lnsects including cockroach excrete nitrogenous waste in the form of soluble potassium urate which is liberated into the haemolymph and taken up by the cells lining the Malpighian tubuies. The tubules facilitate the absorption of urate by stining up the blood. In the cells of the tubule the potassium urate reacts with water and carbon dioxide (from respiration) to form potassium hydrogen carbonate and uric and. The former is absorbed back into the blood, but the later is excreted.
