(a) Unless otherwise authorized by law, all state contracts shall be awarded by the use of one of the following methods:
(1) Competitive sealed bids, pursuant to Section 41-4-132.
(2) Competitive sealed proposals, pursuant to Section 41-4-133.
(3) Small purchase procedures pursuant to Section 41-4-134.
(4) A sole source procurement pursuant to Section 41-4-135.
(5) An emergency procurement pursuant to Section 41-4-136.
(6) A special procurement pursuant to Section 41-4-137.
(b) In the event a bid or offer is received for the supplies or services from a person deemed to be a responsible bidder or offeror and a preferred vendor and the bid is no more than five percent greater than the bid of the lowest responsible bidder or offeror who is not deemed to be a preferred vendor, the Chief Procurement Officer or purchasing agency may award the contract to the preferred vendor.