The commission may deny any application for the issuance of a credential or for the renewal of a credential made by any applicant who falls under any of the following categories:
Any denial pursuant to subdivisions (a) to (e), inclusive, shall be based upon reasons related to the applicant's fitness to teach or fitness to perform other duties for which that applicant is certificated, or competence to perform the duties which the credential would authorize the applicant to perform.
Ca. Educ. Code § 44345