The national debt is approximately

A) $210 million.
B) $21 billion.
C) $210 billion.
D) $21 trillion.

The national debt is currently around $21 trillion, which is a staggering amount. It has been steadily increasing over the years, and it is a major concern for many policymakers and economists. The debt is the sum of all the outstanding debt held by the federal government, including treasury bills, treasury notes, and other securities. It is an important measure of the government's ability to finance its operations and pay off its obligations, and it has important implications for the nation's economic health and stability.