Choose the best alternatives in place of ? out of the four given alternatives (a), (b), (c), (d).
MN: OP :: ? : ?

Options

A. AD:GH
B. AB: PQ
C. QR : ST
D. RS : TV

Answer

To solve the analogy question MN: OP :: ? : ?, we need to identify the relationship between the pairs of letters and apply the same relationship to find the missing pair.

### Step-by-Step Solution:

1. **Identify the relationship between MN and OP:**
- The letters M and N are consecutive letters in the alphabet.
- The letter O comes after N, and P comes after O.
- Specifically, M (13th letter) to O (15th letter) is a jump of 2 positions, and N (14th letter) to P (16th letter) is also a jump of 2 positions.

2. **Establish the pattern:**
- The pattern we see is that each letter in the first pair (MN) is followed by a letter that is two positions ahead in the alphabet to form the second pair (OP).
- Therefore, if we denote the first letter of the new pair as X and the second letter as Y, we can say:
- X = (First letter) + 2
- Y = (Second letter) + 2

3. **Choose the first letter for the new pair:**
- We will start with the letter Q (which is the 17th letter of the alphabet).
- Following the established pattern, we will find the next letter:
- Q (17th letter) + 2 = S (19th letter)

4. **Form the new pair:**
- Thus, the new pair will be Q and S.

5. **Identify the complete sequence:**
- Now we need to find the next two letters after Q and S:
- After S, the next letter is T (20th letter).
- After T, the next letter is U (21st letter).
- Therefore, the complete sequence is QRST.

6. **Select the correct option:**
- Among the given options, we check which one matches QRST:
- Option 1: ADGH (not a match)
- Option 2: ABPQ (not a match)
- Option 3: QRST (this is a match)
- Option 4: RSTV (not a match)
- Hence, the correct answer is option 3: QRST.

### Final Answer:
The correct alternative is **(c) QRST**.