What was the Supreme Court's main purpose in adopting the exclusionary rule?

What was the Supreme Court's main purpose in adopting the exclusionary rule?
 
  a. to allow for regulation of content on the Internet
  b. to allow journalists to withhold information from grand juries
  c. to protect individuals against self-incrimination
  d. to remove any incentive for police misconduct

Question -2-

In Miller v. California, the U.S. Supreme Court held that material must have a deficit of meaningful artistic, literary, political, or scientific worth to be considered __________.
 
  a. obscene
  b. hate speech
  c. fighting words
  d. a prior restraint