Answer:
C. has ruled that campaign spending is a form of free speech
Explanation:
In 2010, The Supreme Court in the case of Citizen United vs. Federal Election Commission (FEC) ruled that, campaign spending is a form of free speech, that is protected under the First Amendment. This ruling hence, effectively give way to corporate bodies or unions to openly support a candidate in an elections, provided they are independent of such campaigns themselves.
In other words, spending money on Candidates for political post is fully accepted or still termed as means of expressing ones fundamental right, which is freedom of speech.