Final answer:
The rear section of the exhaust pipe of a motor vehicle is called the muffler. It reduces noise and helps control emissions.
Step-by-step explanation:
The rear section of the exhaust pipe of a motor vehicle is referred to as the muffler.
Exhaust gas is emitted as a result of the combustion of fuels in the engine, and it passes through the exhaust pipe, where the muffler is located. The muffler is responsible for reducing the noise produced by the engine and also helps to control the emissions by reducing pollutants.
Therefore, the correct answer to the question is muffler (option b).