The Supreme Court .. a. has ruled that candidates cannot solicit campaign contributions from supporters but can receive them if they are unsolicited. b. has ruled that excessive campaign contributions must be strongly regulated by Congress since the electoral process may be in danger of becoming corrupted. c. has ruled that campaign spending is a form of free speech. d. has ruled that it is illegal for candidates to spend more than $10,000 of their own money to run for office. e. has made no comment pertaining to the issue of campaign contributions.

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.