Comprehensive and Detailed Explanation (BIG-IP Administration - Data Plane Concepts):
With Least Connections (member), BIG-IP attempts to send new connections to the pool member with the fewest current connections. In a perfectly "stateless" scenario (no affinity), this often trends toward a fairly even distribution over time.
However, persistence overrides load balancing:
When a persistence profile is applied, BIG-IP will continue sending a client (or client group) to the same pool member based on the persistence record (cookie / source address / SSL session ID, etc.).
This means even if another pool member has fewer connections, BIG-IP may still select the persisted member to honor session affinity.
The result can be uneven active connection counts, even though the configured load balancing method is Least Connections.
Why the other options are not the best cause:
A . Priority Group Activation is disabled
Priority Group Activation only affects selection when priority groups are configured; disabling it does not inherently create uneven distribution under Least Connections.
B . SSL Profile Server is applied
A server-side SSL profile affects encryption to pool members, but it does not by itself cause skewed selection across pool members. (Skew could happen indirectly if members have different performance/latency, but that's not the primary, expected exam answer.) D . Incorrect load balancing method Least Connections is a valid method and does not itself explain unevenness unless something is overriding it (like persistence) or pool members are not all eligible.
Conclusion:
A persistence profile is the most common and expected reason that active connections become unevenly distributed, because persistence takes precedence over the Least Connections load-balancing decision.

These are DoS / SYN flood protection settings, unrelated to persistence or HA behavior.
Explanation:
Comprehensive and Detailed Explanation (BIG-IP Administration - Data Plane Concepts):
This scenario combines session continuity, multiple protocols (HTTP and FTP), and HA failover behavior, which directly implicates persistence handling across devices and services.
Key Requirements Breakdown
Same pool member for entire session
Session must survive failover
Session must span multiple services (HTTP and FTP)
Why Persistence Mirroring + Match Across Services Is Required
Persistence Mirroring
Ensures persistence records are synchronized from the active BIG-IP to the standby BIG-IP.
Without mirroring:
After failover, the standby device has no persistence table
Clients are load-balanced again
Sessions break, forcing users to restart
Persistence mirroring is essential for session continuity during failover Match Across Services Allows a single persistence record to be shared across multiple virtual servers / protocols Required when:
HTTP and FTP must use the same pool member
Multiple services are part of a single application session
Together, these settings ensure:
Persistence survives device failover
Persistence is honored across HTTP and FTP
Why the Other Options Are Incorrect
A . Cookie persistence and session timeout
Cookie persistence only applies to HTTP and does not address FTP or failover synchronization.
B . Stateful failover and Network Failover detection
Stateful failover applies to connection state, not persistence records, and does not link HTTP and FTP sessions.