What can cause rough shifting in an automatic transmission?

Rough shifting in an automatic transmission is most commonly due to low fluid levels, dirty fluid, or malfunctioning components. When the transmission fluid is low, it cannot lubricate and cool the transmission properly, leading to increased friction and difficulty in shifting. Similarly, dirty fluid can cause the transmission to work less effectively, as contaminants can impede the flow of fluid and affect the operation of valves and clutches within the transmission system. Additionally, malfunctioning components, such as solenoids or sensors, can disrupt the transmission's operation, causing erratic or harsh shifts.

Each of these factors directly impacts how well the transmission functions and can lead to noticeable performance issues, such as rough shifting. High temperatures can contribute to transmission problems as well, but they are less likely to be a standalone cause of rough shifting compared to the combination of fluid conditions and component functionality. Conversely, a consistently smooth operation of the vehicle is not only not a cause of rough shifting; it indicates that the transmission is functioning properly. Thus, B is indeed the most comprehensive answer explaining the causes of rough shifting.