The correct answer is D. An Inline Layer is attached to a specific parent rule and is evaluated only after that parent rule matches traffic. This lets administrators create a conditional sub-rulebase. For example, a broad parent rule can match traffic from internal users to the internet, and the inline layer can then apply more granular application or URL decisions. Option A is wrong because there is no separate "Inline Layer Software blade" that must be enabled. Option B is invented terminology;
"Dynamic Layer" is not the requirement. Option C is misleading because inline layers are not
"installed after" ordered layers as an independent step; they are part of the policy package installed to the gateway. The correct enforcement model is conditional: if the parent rule does not match, the inline layer is not entered. If the parent rule does match, the inline layer's rules are evaluated according to normal layer behavior. Reference topics: Ordered Layers, Inline Layers, parent-rule matching, Access Control Policy.