Which of the following effects stability when the boom is extended?

When the boom is extended, retracting it or elevating the boom has a significant impact on the stability of the equipment. Extending a boom raises the center of gravity, which can lead to decreased stability. By retracting or elevating, you can effectively manage and lower the center of gravity and improve the machine's overall balance. This is essential when handling loads since a stable working platform reduces the risk of tipping or losing control of the equipment.

Retracting or elevating adjusts the position of the boom, often aligning it better with the center of gravity of the load being lifted, which enhances stability during operations. Therefore, the relationship between the boom's position and the stability of the equipment is critical, making this the correct answer.