What may be unsafe for a bus when driving through a turn?

Answer: B — The posted speed for a turn

Driving through a turn safely is crucial, especially for a bus, which is larger and heavier than most other vehicles. The posted speed for a turn is specifically designed to optimize safety and ensure that vehicles can navigate the turn without losing control or tipping over. If a bus exceeds this posted speed, it can result in instability during the turn due to its high center of gravity and wide wheelbase, increasing the risk of skidding or overturning. When a bus takes a turn too quickly, it increases the likelihood of causing a dangerous situation not only for the passengers aboard but also for other road users. Therefore, adhering to the posted speed limit for turns is essential for maintaining control and ensuring the safety of everyone involved.