Use the following information to answer the next question.SecurityAmount (in billions)Treasury bills$220Corporate bonds140Treasury notes80Corporate stock200U.S. savings bonds60Treasury bonds100Other things equal, an increase of Treasury bonds from $100 billion to $120 billion in the economy would

A. not change the size of the public debt.
B. increase the public debt from $400 billion to $420 billion.
C. decrease the public debt by $20 billion.
D. increase the public debt from $460 billion to $480 billion.

D