Answer - B
The Transport layer (also known as the Host-to-Host Transport layer) is responsible for providing the Application layer with session and datagram communication services. The core protocols of the Transport layer are Transmission Control Protocol (TCP) and the User Datagram Protocol (UDP).
For more information on the TCP IP Model, one can visit the below URL:
https://technet.microsoft.com/en-us/library/cc958821.aspx