Which California city houses one of the major EOD units?

The correct choice, Imperial Beach, is significant because it is home to one of the major Explosive Ordnance Disposal (EOD) units, known as Naval Base Coronado, which operates in that area. The location is strategically important due to its proximity to the Pacific Ocean, facilitating training and operational readiness for EOD personnel, particularly in relation to maritime operations and amphibious warfare.

On the other hand, while San Diego houses a number of important naval facilities and units, including various special operations and support units, it is not specifically designated as the major base for an EOD unit. Los Angeles, being a large metropolitan area, does not serve as a primary location for any major EOD operations or units. Santa Barbara, also a beautiful coastal city, does not host the major EOD units, making Imperial Beach the most accurate answer in this context.