End to end connectivity is provided from host to host in : 

The correct answer is Transport layer.

Key Points

• The Transport layer is responsible for end-to-end communication and error handling between host systems.
  • It ensures that data is transmitted across a network in a reliable manner.
  • Protocols like TCP (Transmission Control Protocol) and UDP (User Datagram Protocol) operate at this layer.
  • The Transport layer segments and reassembles data into a data stream.
  • This layer provides flow control, ensuring that data is sent at a rate that matches the receiver's ability to process it.
  • Error detection and correction mechanisms are implemented at this layer to ensure data integrity.

Additional Information

• The Transport layer is the fourth layer in the OSI (Open Systems Interconnection) model, sitting above the Network layer and below the Session layer.
• It is essential for ensuring that data sent from an application on one host can be correctly received by an application on another host.
• Common applications that rely on the Transport layer include web browsers, email clients, and file transfer programs.
• The Transport layer can also provide multiplexing, allowing multiple applications to use the network simultaneously without interfering with each other.