The correct answer is: A. Block Development Officer
The Block Development Officer (BDO) is the executive officer of the Panchayat Samiti. The BDO is responsible for the implementation of government schemes and programs in the block. The BDO also supervises the work of the Panchayat Samiti staff.
The Sub-Divisional Magistrate (SDM) is a revenue officer who is responsible for the administration of a sub-division. The SDM is not the executive officer of the Panchayat Samiti.
The Sub-Divisional Officer (SDO) is an engineering officer who is responsible for the maintenance of roads, bridges, and other infrastructure in a sub-division. The SDO is not the executive officer of the Panchayat Samiti.
The Sarpanch is the elected head of a Gram Panchayat. The Sarpanch is not the executive officer of the Panchayat Samiti.