Which best describes the relationship between maximum cost-per-click (CPC) bids and Ad Rank

Which best describes the relationship between maximum cost-per-click (CPC) bids and Ad Rank

  A)  An increased CPC bid leads directly to a small increase in Ad Rank
  B)  CPC bid only affects Ad Rank on the Search Network
  C)  An increased CPC bid leads directly to a large increase in Ad Rank
  D)  CPC bid is one factor that affects Ad Rank