Each (A), (B), and (C) are distinct criteria's for meeting the requirement. Just as 15.403-1(b)(1),(2),(3),(4), or (5) are each distinct. Can adequate competition be meet for my scenario per FAR 52.403(c)(I)(C)? If not why and what options do I have?
The FAR defines adequate price competition in FAR 15.403-1, which applies to the prohibition of requesting certified cost or pricing data. FAR 15.403-1(c) lists the exceptions for certified cost or pricing data requirements, and adequate price competition is one of the exceptions. Since adequate price competition is not defined in FAR part 2 or 16, the Contracting Officer can choose to use the definition found in FAR part 15 as a basis for their actions unless prohibited to do so in the applicable FAR part they are working under.
FAR 15.403-1(c)(1)(i)(A) states "Two or more responsible offerors, competing independently, submit priced offers that satisfy the Government’s expressed requirement". If there are technically unacceptable offers, then those are not satisfying the Government's expressed requirement. Each contractor who was found to be technically unacceptable has pricing tied to an unacceptable technical approach, and therefore is not fair and reasonable.
If the ordering terms of the IDIQ do not prohibit otherwise, allow the two offerors who have technically unacceptable offers to update their technical proposals. Both must be allowed to update their proposals to ensure fairness. When there are at least two technically acceptable offerors, then there will be adequate price competition.