The correct answer is A. 1958.
Assam State Electricity Board (ASEB) was constituted in 1958. It is a state-owned enterprise under the Government of Assam. ASEB is responsible for the generation, transmission, and distribution of electricity in the state of Assam.
ASEB has a total installed capacity of 2,500 MW. It generates electricity from thermal, hydro, and renewable sources. ASEB has a transmission network of over 10,000 km and a distribution network of over 30,000 km.
ASEB supplies electricity to over 10 million consumers in the state of Assam. It is one of the largest power utilities in India.
Option B is incorrect because Assam State Electricity Board (ASEB) was not constituted in 1950.
Option C is incorrect because Assam State Electricity Board (ASEB) was not constituted in 1960.
Option D is incorrect because Assam State Electricity Board (ASEB) was not constituted in 1970.