Which of the following is an example of a contact force?

Which of the following are characteristics of soft money? i. donations from individuals and interest group pacs ii. unregulated by the federal election commission iii. goes directly to a political candidate iv. can be used for advertising or other campaign expenses a. i, ii, iii, and iv b. i and ii only c. i, iii, and iv only d. ii, iii, and iv only\