Final answer:
A B Train coupling mechanism allows for more flexible turning.
Step-by-step explanation:
The correct statement about a B Train coupling mechanism is c) It allows for more flexible turning. A B Train is a type of truck-trailer combination commonly used in North America. It consists of a truck-tractor pulling two semi-trailers, with one trailer being attached to the back of the other.
The B Train coupling system allows for better maneuverability and turning radius compared to other types of truck-trailer configurations. This is because the second trailer's wheels track inside the path of the first trailer's wheels. This flexibility is especially useful when navigating tight corners and narrow spaces.