To answer this question, the user needs to know about the SOAP protocol and its binding element.
The SOAP protocol is an XML-based messaging protocol used to exchange information between different systems. The soap:binding element is used to define the binding of a web service operation to a particular communication protocol.
The soap:binding element has two attributes:
A. style attribute: This attribute is used to define the encoding style used for the message. It specifies whether the message is encoded using the SOAP encoding rules or some other encoding rules.
B. transport attribute: This attribute is used to specify the communication protocol used for the message. It specifies the transport protocol used for sending and receiving the SOAP message. The transport protocol can be HTTP, SMTP, or any other protocol.
C. message attribute: This attribute is not a valid attribute for the soap:binding element. The message attribute is used in the soap:operation element to specify the input and output messages for the operation.
Therefore, the correct answer is:
B. Both 1 and 3