Final answer:
Infants and young children should be placed in a rear-facing car seat in the back seat of a vehicle for maximum safety. The back seat protects them better and the rear-facing position is critical for the safety of young children's heads, necks, and spines during travel.
Step-by-step explanation:
Infants and young children should ride in a rear-facing car seat located in the back seat of a vehicle. This is because the back seat is the safest place for young children, and a rear-facing car seat provides the best support for their head, neck, and spine in the event of a sudden stop or crash. It is important to keep children in a rear-facing car seat for as long as possible, at least until they reach the height and weight limits specified by the car seat manufacturer.
Using a booster seat in the front seat is not as safe for young children, and allowing a child to ride unrestrained in any part of the vehicle is extremely dangerous and illegal. Moreover, the front passenger seat is not a suitable place for infants and young children due to the potential impact of airbags in a crash. Therefore, the correct answer to where infants and young children should ride in a vehicle is: B) Rear-facing car seat in the back seat.