Consider the following statements regarding three-tier panchayati raj system: 1. The panchayat samiti is the executive body while the zila parishad is advisory, coordinating and supervisory body. 2. The three-tier panchayati raj system was recommended by the Ashok Mehta Committee. 3. Balwant Rai Mehta Committee had recommended that the three-tier system of panchayati raj should be replaced by the two-tier system. Which of the above statement(s) is/are correct?