The correct answer is: d) 31%.
The percentage of reservation for OBCs in Tamil Nadu is currently 31%. This means that 31% of all seats in government jobs and educational institutions are reserved for OBCs. This reservation was implemented in order to provide equal opportunities to OBCs, who have historically been disadvantaged in Indian society.
The other options are incorrect. Option a) is incorrect because the percentage of reservation for OBCs in Tamil Nadu is not 27%. Option b) is incorrect because the percentage of reservation for OBCs in Tamil Nadu is not 50%. Option c) is incorrect because the percentage of reservation for OBCs in Tamil Nadu is not 69%.