Which term describes an assembly including diesel and electric units controlled together?

The correct term describing an assembly including diesel and electric units controlled together is represented by the option that refers specifically to a train setup involving a combination of these power sources. In railway terminology, "engine" generally refers to the motive power used to pull or push the train, which can encompass both diesel and electric locomotives when they operate in tandem as a single control unit.

When multiple units are controlled together, it reflects a fundamental aspect of modern rail operations where efficiency and versatility are achieved by integrating different types of locomotives. This allows for a seamless driving experience and improved operational effectiveness.

The other terms, such as "equipment," "light engine," and "M-Series Equipment," refer to different aspects of railway operations but do not accurately capture the specific arrangement of diesel and electric units working in unison as the term "engine" does in this context. "Light engine" usually refers to a locomotive running without any attached train cars, and "M-Series Equipment" could specify a particular type of commuter train but does not encompass the general assembly of both diesel and electric units.