Section 31(a) in The Chartered Accountants (Election to the Council) Rules, 2006
(a)if a voter signs his name or writes any word or figure upon it or makes any mark including a tick (√)/cross (x), not being a mark of 'x' put under clause (c) of sub-rule (2) of rule 20, upon it by which the ballot paper becomes recognizable or by which the voter can be identified; or
