The correct answer is (b), Legislature of State.
The Constitution of India, Article 243(D), states that the Legislature of a State may, by law, make provisions with respect to the composition of Panchayats. The Legislature of a State may also make provisions with respect to the number of seats in each Panchayat, the manner in which the seats are to be filled, the qualifications and disqualifications for membership, the term of office of members, and the manner in which vacancies are to be filled.
The Governor of a State has no power to make provisions with respect to the composition of Panchayats. The Parliament of India also has no power to make provisions with respect to the composition of Panchayats. The President of India has no power to make provisions with respect to the composition of Panchayats.
The Legislature of a State is the only body that is authorized to make provisions with respect to the composition of Panchayats.