Step 1: Qualification under Advocates Act.
Section 24 of the Advocates Act, 1961 specifies that the minimum age requirement is 21 years. However, this provision has been changed and now the minimum requirement is completion of law degree (no fixed minimum age beyond 21 years completion is separately insisted).
Step 2: Clarification.
Other qualifications such as Indian citizenship, and absence of conviction for moral turpitude or offences under the Untouchability Act remain valid.
Step 3: Conclusion.
Thus, statement (a) is outdated/untrue and is the correct answer.