Explanation
Wireshark and Shodan are two tools that can be used to perform passive reconnaissance, which means collecting information from publicly available sources without interacting with the target or revealing one's identity. Wireshark is a tool that can be used to capture and analyze network traffic, such as packets, protocols, or sessions, without sending any data to the target. Shodan is a tool that can be used to search for devices or services on the internet, such as web servers, routers, cameras, or firewalls, without contacting them directly.
The other tools are not passive reconnaissance tools, but rather active reconnaissance tools, which means interacting with the target or sending data to it. Nessus and Retina are tools that can be used to perform vulnerability scanning, which involves sending probes or requests to the target and analyzing its responses for potential weaknesses. Burp Suite is a tool that can be used to perform web application testing, which involves intercepting and modifying web requests and responses between the browser and the server.