Answer:
Option B i.e., Circuit level gateways only enable data to be inserted into a network which is the product of system requests within the network.
Explanation:
In the above question, some details are missing in the question that is options.
Option B is valid because Circuit level gateways are not the transmission inspection, always require information into such a server resulting through system appeal inside the server through maintaining a record for connections that are sent into the server and only enabling information in this is in answer to such queries.
Other options are incorrect because they are not true according to the following scenario.
