Step 1: Understanding the Concept:
The question asks for the minimum number of members required to apply for the registration of a trade union under the relevant Indian law.
Step 2: Detailed Explanation:
The formation and registration of trade unions in India are governed by the Trade Unions Act, 1926.
Section 4(1) of the Act deals with the 'Mode of registration'. It states that "Any seven or more members of a trade union may, by subscribing their names to the rules of the trade union and by otherwise complying with the provisions of this Act with respect to registration, apply for registration of the trade union under this Act."
Therefore, the minimum number of persons required to sign the application for registration is seven. There is also a further condition that a registered trade union must at all times continue to have not less than ten percent or one hundred of the workmen, whichever is less, subject to a minimum of seven. But for the initial formation and application, the number is seven.
Step 3: Final Answer:
The minimum number of persons required to form and apply for the registration of a trade union is seven. Therefore, option (B) is the correct answer.