Which of these factors contributed MOST to the change in national debt between 1981 and 19 A A decline in business subsidies, which discouraged exports B An expansion of the military during the Cold War C A reduction in government services which led to rising poverty rates D A period of economic growth that promoted inflation

## Step 1: Analyze the Time Period<br />### The question asks about the change in national debt between 1981 and 1993, which corresponds to the Reagan/Bush era on the graph. During this period, the graph shows an increase in federal debt as a percentage of GDP.<br /><br />## Step 2: Evaluate the Options<br />### - **Option (A)**: A decline in business subsidies would likely reduce government spending, potentially decreasing debt, not increasing it.<br />### - **Option (B)**: An expansion of the military during the Cold War is historically accurate for this period. The Reagan administration significantly increased military spending, contributing to higher national debt.<br />### - **Option (C)**: A reduction in government services might decrease spending, which would not typically lead to an increase in debt.<br />### - **Option (D)**: Economic growth generally leads to increased revenues, which could help reduce debt unless offset by significant increases in spending.<br /><br />## Step 3: Determine the Most Likely Factor<br />### Given historical context, the most significant factor contributing to the increase in national debt during this period was the substantial increase in military spending due to Cold War policies.