Diesel exhaust fluid is injected A. after the oxidation catalyst. B. at the end of the tail pipe. C. into the exhaust manifold. D. solely in front of the muffler

Answer - C

Diesel exhaust fluid (DEF; an aqueous urea solution) is injected into the exhaust manifold (upstream of a catalyst) at a precise dosing rate. In the exhaust pipeline, the aqueous urea vaporizes and decomposes to form ammonia (which is the desired product) and carbon dioxide.