Which of the following is not a focus area of the Electric Shop?

The Electric Shop primarily focuses on the maintenance and repair of electrical equipment and systems that are crucial for the operational capabilities of aircraft. This includes areas such as generator maintenance, radar equipment, and electrical systems, all of which are directly related to the shop's responsibilities for electrical and avionics systems.

Oxygen systems, on the other hand, do not fall under the purview of the Electric Shop. Instead, they are typically managed by a different department, often associated with life support systems or environmental control systems. Therefore, identifying oxygen systems as not being a focus area of the Electric Shop highlights the shop's specific emphasis on electrical systems rather than systems related to crew safety or environmental control.