Which of the following is not a mandatory insurance for California contractors?

General liability insurance is a type of coverage that is commonly recommended for contractors to protect against claims of bodily injury, property damage, and personal injury arising from their work. However, it is not mandated by California law for contractors.

In contrast, workers' compensation insurance is a legal requirement for contractors in California who have employees, providing coverage for employees who may be injured on the job. Similarly, builder’s risk insurance is often required in specific contractual agreements to cover construction projects against unforeseen damages. Auto insurance can also be necessary, particularly if the contractor uses vehicles for business purposes, though it is not mandated under contractor licensing laws. Therefore, among the options presented, general liability insurance stands out as it is not a requirement enforced by California contractors' licensing laws.