Question

Match List-I with List-II:

List-I (Counters)	List-II (Delay/Number of States)
(A) n-bit ring counter	(I) Number of states is \( 2^n \)
(B) MOD-\(2^n\) asynchronous counter	(II) Fastest counter
(C) n-bit Johnson counter	(III) Number of used states is \( n \)
(D) Synchronous counter	(IV) Number of used states is \( 2n \)

Choose the correct answer from the options given below:

• (A) – (I), (B) – (II), (C) – (III), (D) – (IV)
• (A) – (I), (B) – (III), (C) – (II), (D) – (IV)
• (A) – (I), (B) – (II), (C) – (IV), (D) – (III)
• (A) – (III), (B) – (I), (C) – (IV), (D) – (II)

Hint:

When matching counters, focus on \textit{number of states} and \textit{speed} as key properties.

Answer 1

The Correct Option is D

Step 1: Recall definitions of counters.
- Ring counter uses $n$ states.
- MOD-$2^n$ asynchronous counter has $2^n$ states.
- Johnson counter uses $2n$ states.
- Synchronous counter is fastest.

Step 2: Match accordingly.
Thus, (A)–(III), (B)–(I), (C)–(IV), (D)–(II).
Final Answer: \[ \boxed{(4)} \]