A nuclear power plant supplying electrical power to the village uses a radioactive material of half life T years as the fuel. The amount of fuel at the beginning such that the total power requirement of the village is 12.5 % of the electrical power available from the plant at that time. If the plant is able to meet the total power needs of the village for a maximum period of n T years, then the value of n is

1) 1
2) 3
3) 5
4) 7