D. issuing Treasury bonds and other government-backed securities
Step-by-step explanation:
Governments create debt by issuing government bonds and bills. Less creditworthy countries sometimes borrow directly from a supranational organization (e.g. the World Bank) or international financial institutions.
Treasury bonds are how the US - and all governments for that matter - borrow hard cash: they issue government securities, which other countries and institutions buy. So, the US national debt is owned mostly in the US - but the $5.4tn foreign-owned debt is owned predominantly by Asian economies.
