(c) In addition to the procedure set forth above in subsections (a) and (b) of this section, the charter may be revised or amended by the submission of a citizen initiative (petition) signed by 10 percent of the voters. The petition and subsequent action shall conform to the requirements of State statutes relating to charter amendment procedures, shall be subject to the determination of the Board of Selectmen as to whether or not they are comprehensive in nature, and shall be approved by a Town meeting vote with at least 25 percent of voters participating.