The corporations and unions have been able to spend unlimited sums of money on campaign advertising since 2010 because the Supreme Court ruled that campaign spending is a protected form of free speech.
Answer: Option B
Explanation:
The Supreme Court in its judgement of a 2010 case fought between the parties 'Citizen United' and the 'Federal Election Commission' clarified that the expenditure made by a political party to communicate with its subjects forms an integral part of their freedom of speech and hence their spending on election campaigns cannot be capped by law.