Two Down Still Correct

A leaderless store keeps $N = 5$ replicas per key. Strict quorums only: no sloppy quorum, no hinted handoff. The requirement from the product team is blunt: while any 2 of the 5 replicas are down, reads and writes must both keep succeeding, and a read must never miss a write that was already acknowledged.

Which $(R, W)$ is the only pair that satisfies all of that?