Describe what trenching is in relation to excavator operations.

Trenching in excavator operations refers specifically to the act of digging a long, narrow excavation, making option B the correct description. This technique is commonly used for various purposes, such as installing utilities, drainage systems, or foundation footings. In a trench, the width is typically much less than the length and depth, thereby creating a channel-like shape that serves specific functional needs.

The design of trenches allows for effective access to underground installations while minimizing the amount of displaced earth. Proper trenching is critical for safety and stability, necessitating knowledge about the optimal dimensions and engineering practices to prevent collapse and ensure that the excavation meets the required specifications for whatever infrastructure is being installed.

The other options do not accurately encapsulate the nature of trenching. For instance, digging wide shallow holes does not fit the definition of trenching due to its broader context and lack of a narrow aspect. Filling holes with concrete is a completely different operation that involves backfilling, which comes after excavation, rather than the act of trenching itself. Surface grading pertains to leveling the ground surface, which is unrelated to the focused and purposeful excavation that trenching entails.