Minimum training requirement for tonnage tax companies requires certified compliance with returns; prolonged noncompliance terminates the tonnage option. A tonnage tax company must meet a minimum training requirement for trainee officers per guidelines of the Director General of Shipping and submit, with its return of income under section 139, a certificate from the Director General certifying compliance for the previous year. Sustained consecutive noncompliance for an extended period will cause the company's option for the tonnage tax scheme to cease to have effect from the beginning of the previous year following the last year of such noncompliance.