What are the two items that cause a Reduced Performance light?

The cause of a Reduced Performance light is related to specific components that can hinder the overall efficiency and function of the system. The option identifying the electronic parking brakes (EP brakes) that won't release, combined with the Transmission Control Unit (TCU), is correct because these two items directly impact how the vehicle operates.

When the electronic parking brakes fail to release, it can create a significant drag on the vehicle, leading to reduced performance. This situation can manifest in sluggish acceleration or inability to reach optimal speed. Additionally, if the Transmission Control Unit detects a problem, it will adjust the vehicle's performance to prevent further damage, resulting in a performance alert being activated. Therefore, the combination of these two critical elements is a plausible reason for the Reduced Performance light appearing.