Which statement correctly describes the behavior of a static route configured on a FortiGate when using a blackhole route?

The statement that traffic routed by a blackhole does not create session entries in the session table is correct.

A blackhole route is a special type of static route that is used to discard packets destined for a specific subnet. When traffic is directed to a blackhole route, it is essentially "dropped" by the FortiGate without sending any notification back to the sender. This is significant because it means that, unlike regular traffic, which would generate session entries in the session table to track the connections and state, traffic routed through a blackhole does not create these session entries. This approach helps to minimize resource usage on the device since there is no active session management for the dropped traffic.

Other options address behaviors that are not characteristics of a blackhole route. For instance, while it is true that blackhole routes drop traffic, simply stating that all traffic is dropped does not capture the nuance of how session management works in this scenario. Similarly, routing through a backup device or redirecting traffic to a different interface does not apply to blackhole routes, as their purpose is strictly to discard traffic without creating stateful session records.