Explanation:

The Indian Administrative Service often abbreviated to I.A.S., or simply IAS, is the administrative arm of the All India Services. Considered the premier civil service of India, the IAS is one of the three arms of the All India Services along with the Indian Police Service (IPS) and the Indian Forest Service (IFS). Members of these three services serve the Government of India as well as the individual states. IAS officers may also be deployed to various public sector undertakings.