The Committee on Estimates is the largest among the options provided and is the largest of the three Financial Committees of the Parliament. It consists of 30 members, all of whom are elected annually by the Lok Sabha from amongst its members. Notably, the Rajya Sabha has no representation in this committee.

Comparison of Committee Sizes:

• Committee on Estimates: 30 members (All from Lok Sabha).
• Committee on Public Accounts: 22 members (15 from Lok Sabha and 7 from Rajya Sabha).
• Committee on Public Undertakings: 22 members (15 from Lok Sabha and 7 from Rajya Sabha).
• Committee on Petitions: The Lok Sabha committee consists of 15 members, while the Rajya Sabha committee consists of 10 members.

While Department-Related Standing Committees (DRSCs) created in 1993 have 31 members, the Committee on Estimates remains the largest committee of the Lok Sabha and the largest among the specific choices listed in the question.