Match List-I with List-II.

	List – I		List – II
A.	SMTP	I.	Network layer
B.	UDP	II.	Transport layer
C.	Ethernet	III.	Application layer
D.	IP	IV.	Data Link layer

Choose the correct answer from the options given below:

Correct option is B

We need to match each protocol/technology with its corresponding OSI layer.
A. SMTP → III. Application Layer
SMTP (Simple Mail Transfer Protocol) is used for sending email over a network. It operates at the Application Layer (Layer 7) of the OSI model.
B. UDP → II. Transport Layer
UDP (User Datagram Protocol) is a connectionless transport-layer protocol. It provides process-to-process communication using port numbers.
C. Ethernet → IV. Data Link Layer
Ethernet is primarily associated with the Data Link Layer (Layer 2) for framing and MAC addressing. In the OSI model, Ethernet standards cover both the Physical Layer and Data Link Layer, but in this matching question, Ethernet corresponds to the Data Link Layer.
D. IP → I. Network Layer
IP (Internet Protocol) is responsible for logical addressing and routing packets between networks. It operates at the Network Layer (Layer 3).
Information Booster
1. SMTP → Application Layer → Email transmission.
2. UDP → Transport Layer → Connectionless communication.
3. Ethernet → Data Link Layer → Framing and MAC addressing.
4. IP → Network Layer → Logical addressing and routing.