After each ballot box and also each sealed cover (if any) received under sub-rule (5) of rule 26, has been opened, the Returning Officer shall—
(a) count the number of ballot papers taken out therefrom and complete Part II of the Ballot Paper Account in Form 6 ;
(b) scrutinise the ballot papers and separate those which in his opinion are valid from those which in his opinion are invalid, endorsing on the latter the word 'rejected' and the ground of rejection ; and
(c) arrange all the valid ballot papers in parcels according to the first preferences recorded for each candidate:
Provided that if, at a Presidential election, the ballot box used at a place of polling contains ballot papers of electors who, at their request are specially permitted by the Election Commission in pursuance of rule 7 to cast their votes at the said place of polling, such ballot papers shall, after the counting and recording in Form 6 is completed, be separated and added to the other ballot papers of the same kind used by electors in the same category and shall thereafter be scrutinised.