Answer:
The public debt is D. all federal government debt irrespective of who owns it.
Explanation:
Public debt mainly defined as the total liabilities of federal government. This is called the government debt. It includes outside and inside debt as well. The government borrowes from international institutions like world bank for the development of the nation. This comes under external debt. The money which the government owes inside the nation comes under internal debt.
All other options are incorrect as first option relates with unfavourable balance of payments. Second one is related with government securities only and other one is the favourable balance of payments.