Suppose the Stock of Government Debt in Canada at the End

Suppose the stock of government debt in Canada at the end of one fiscal year (Year 1) is $475 billion.During the following year (Year 2) ,government purchases were $180 billion,debt-service payments were $25 billion,and net tax revenues were $208 billion.What is the stock of debt at the end of Year 2?

A) $422 billion
B) $457 billion
C) $472 billion
D) $475 billion
E) $478 billion