Even Though the National Debt Is Rising, the Debt-To-GDP Ratio

Even though the national debt is rising, the debt-to-GDP ratio will fall as long as

A) interest payments on the national debt as a fraction of government spending remain constant
B) the real interest rate exceeds the economic growth rate and the primary budget is balanced
C) the real interest rate is lower than the economic growth rate and the primary deficit is zero
D) the debt is growing more slowly than the federal budget deficit
E) the primary budget deficit as a share of GDP is not growing