(d)__That the circulator believes them to be genuine signatures of the persons whose names they purport to be;

(e)__That each signer has signed no more than one petition; and

(f)__That each signer had an opportunity to read the petition before signing.

C. Petition forms under this subsection must be assembled as one instrument and filed at one time with the clerk of the municipal service district. The clerk shall note the date of filing on the forms.

D.__Within 20 days after the petition is filed pursuant to paragraph C, the clerk of the municipal service district shall complete a certificate as to its sufficiency, specifying, if it is insufficient, the particulars that render it defective. The clerk shall promptly send a copy of the certificate to the petitioners' committee by mail and shall file a copy with the municipal service district officers.__The clerk of each participating municipality shall cooperate as necessary to assist the clerk of the municipal service district in completing the certificate required under this subsection.

E.__A petition certified insufficient under paragraph D for lack of the required number of valid signatures may be amended once if the petitioners' committee files a notice of intention to amend the petition with the clerk of the municipal service district within 2 days after receiving the copy of the clerk's certificate.__The procedure regarding submission and review of a supplementary petition is as follows.

(1)__Within 10 days after the notice of intention is filed, the committee may file a supplementary petition to correct the deficiencies in the original. This supplementary petition, in form and content, must comply with the requirements for an original petition under paragraphs A to C.

(2)__Within 5 days after a supplementary petition is filed, the clerk shall complete and file a certificate