Explanation:

Only statement 2nd is correct.

• According to Section 62(5) of the Representation of the People Act, 1951, A Person can not vote at any election if he is confined in a prison, whether under a sentence of imprisonment or transportation or otherwise, or is in the lawful custody of the police.
• According to the Section 62(5) of the Representation of the People Act, 1951, a person subjected to preventive detention under any law is entitled to vote by Postal Ballot paper.
• Every Indian citizen with disability or reduced mobility / functions who has attained the age of 18 years on the qualifying date i.e. first day of January of the year of revision of electoral roll, unless otherwise disqualified of crime or unsound mind as declared by a competent court ,is eligible to be registered as a voter.

Hence option 3rd is correct.