Every person to whom the provisions of section 11 are applicable shall be liable to be called up for inquiry under section 13,--
         (a) if he belongs to any of the classes specified in clauses (a) to (f) of sub-section (1) of section 11, until he has completed his thirty-seventh year, and
         (b) if he belongs to any of the classes specified in clauses (g) and (h) of the said sub-section, until he has completed his fiftieth year.