The correct answer is D. WebSocket is a stateful, bidirectional, and connection-oriented protocol.
A stateful protocol is one that maintains state between requests. This means that the server can keep track of the client’s current state and respond accordingly. For example, a stateful protocol could be used to keep track of a user’s shopping cart in an online store.
A bidirectional protocol is one that allows for communication in both directions. This means that the client can send messages to the server, and the server can send messages to the client. This is in contrast to a unidirectional protocol, which only allows for communication in one direction.
A connection-oriented protocol is one that establishes a dedicated connection between the client and the server. This means that the client and the server are able to communicate with each other even if there are other users or applications using the same network. This is in contrast to a connectionless protocol, which does not establish a dedicated connection.
WebSocket is a stateful, bidirectional, and connection-oriented protocol that is used to create a persistent connection between a client and a server. This allows for real-time communication between the client and the server, which is useful for applications such as chat, video conferencing, and online gaming.