Option 2, "Compiling the accounts of Defence," is not a function of the Comptroller and Auditor General (CAG) of India.

The CAG is a constitutional authority responsible for auditing the financial transactions of the central and state governments in India. The functions of the CAG include auditing the transactions of the Centre and State Governments relating to contingency funds and public accounts, auditing the accounts of institutions financed by the government, and compiling the accounts of states.

However, compiling the accounts of Defence is not a specified function of the CAG. It is the responsibility of the Defence Accounts Department (DAD) to maintain and compile the financial accounts of the Indian Defense services. The DAD operates independently of the CAG, although the CAG may conduct audits of the accounts maintained by the DAD.

In conclusion, while options 1, 3, and 4 are all valid functions of the CAG, option 2, "Compiling the accounts of Defence," is not a function assigned to the CAG.