Answer:
c. SSL Certificate
Explanation:
The full form of SSL is Secure Sockets Layer. It is the standard security technology which establishes the encrypted link between a client and the server—typically a web server (which is the website) and the browser, or the mail server along with a mail client (for e.g., Outlook).
In the context, in order to develop an SSL connection, an SSL Certificate is required by the Web server.