How Obama Raised More Campaign Money by Declining Federal Funds

How Obama raised more campaign money by declining federal funds Source: Federal Election Commission reports.
-Based on the graph,how did refusing federal funds affect Obama's campaign spending?

A) Obama had less to spend than the candidates against whom he ran.
B) Obama spent all of his money seeking his party's nomination.
C) Obama was required to use his own personal funds for his campaign.-Consider This: Refusing federal funds enables candidates to raise more money from other sources; they are not required to use their own money.
D) Obama was able to raise and spend much more than if he used federal funds.