The correct option is A 6
The reaction of the reduction is,
BrO−3+6e−+3H2O→Br−+6OH−
The oxidation state of Br in BrO−3 is +5 and reduced to −1. Hence, 6 electrons are involved in the reaction.
One faraday of charge is the magnitude of the charge of one mole of electrons.
Thus, 6 faradays are required for this reaction.
Hence, option (c) is correct.