The correct answer is D) narcotics.
The commodity that the US federal government continued to target in order to defund terrorists and fight corrupt political regimes throughout the world is narcotics.
After the attacks of 9/11, the federal government of the United States intensified the war against terrorism. President George W. Bush created the Department of Homeland Security to work with other agencies to fight terrorism and cut the funds of terrorist cells that many times get their money through narcotics. That is the reason of existence for the DEA, the Drug Enforcement Administration, that combats drug cartels. The US is aware that if they follow the money, can defund these criminal organizations.