Given that there are at most two failures at a time in the system, which of the following protocols does NOT satisfy completeness? $(1$ point$)$

$1$ point

Ring$-$style heartbeating where each process heartbeats to both its clockwise neighbor and anticlockwise neighbor

Ring$-$style heartbeating where each process heartbeats to only its clockwise neighbor

All$-$to$-$all heartbeating

Gossip$-$style heartbeating