6. The director may deny the application of any person for an instructor's license or for a motorcycle safety education instructor endorsement to an instructor's license if, in his discretion, he determines that:
a. the applicant has made a material false statement or concealed a material fact in connection with his application therefor;
b. the applicant has failed to furnish satisfactory evidence of the facts required of him in section five of this act; or
c. the applicant for an instructor's license is not of good moral character; that he has not held a license to drive a motor vehicle within the State for the past three consecutive years; that he has not had a driving record satisfactory to the director; that he has been convicted of crime; that he is disqualified for a motorcycle safety education instructor endorsement for any reason set forth in section 2 of P.L.1991, c.452 (C.27:5F-37).