Explanation:

Minor who is member of registered trade union can enjoy all the rights of member just like any other members. That's why Third statement is incorrect 

Section 21 : rights of minors to membership of trade union

Secttion 21 provides that a person who is above 15 years of age can be  a member of any trade union, and if he becomes a member, he can enjoy all the rights conferred upon the members of the trade union, subject to the conditions laid down by the trade union of which he wants to be a member.

Section 21-A : disqualifications of office-bearers of trade union

Secttion 21 of the Act lays down the conditions, the fulfilment of which disqualifies a person from being a member of the trade union. The conditions laid down in the Act are as follows:

• If the member has not attained the age of majority
• If he has been convicted by any of the courts in India for moral turpitude and has been sentenced to imprisonment unless a period of five years has elapsed since his release.