Within five days after the mailing of written notice of removal, discharge, or suspension, any employee may file a written request with the general manager for an opportunity to be heard in his own defense or, at the employee’s option, may utilize a grievance procedure if the district and a recognized employee organization have agreed after meeting and conferring in good faith pursuant to Section 3505 of the Government Code that a grievance procedure may be used in disciplinary proceedings involving removals, discharges, and suspensions as an alternative to the procedure provided for in Sections 12165 and 12166.