Credit Card Debt for 10 People Was Compared Before a Major

Multiple Choice

Credit card debt for 10 people was compared before a major economic crash (perhaps one like that of 2008) and then after economic recovery, let's say 5 years later.Which of the following is an appropriate null hypothesis for this research?

A) Economic recoveries have no impact on debt carried by citizens.
B) Credit card debt will be different after economic recovery compared to just prior to an economic crash.
C) Credit card debt increases over time.
D) Credit card debt before the economic crash will be approximately the same as that after the economic recovery.