All pool members are online.

By default, BIG-IP load balancing algorithms (such as Round Robin) distribute connections evenly across all available pool members. However,persistence profiles override normal load balancing decisionsby forcing subsequent connections from a client to be sent to the same pool member.

According to theBIG-IP Administration: Data Plane Configurationdocumentation:

Persistence creates aclient-to-server mappingthat is honored before load balancing algorithms are applied.

When persistence is enabled, BIG-IP may repeatedly select the same pool member even if others are available.

This directly alters load balancing behavior.

Why the other options are incorrect:

A. Adding a OneConnect profileOneConnect optimizes server-side TCP connections but does not change which pool member is selected.

B. Enabling SNAT automapSNAT affects source address translation, not pool member selection.

C. Enabling a fallback host in the HTTP profileA fallback host is only used when no pool members are available.

Correct Resolution:

Adding apersistence profilealters load balancing behavior by maintaining client affinity to a specific pool member.