Find the next letter-pair in the following series.
BT, EQ, HN,?

Options

A. GC
B. KZ
C. KG
D. KK

Answer

To find the next letter-pair in the series BT, EQ, HN, we will analyze the pattern in the letters.

### Step-by-Step Solution:

1. **Identify the Letters in Each Pair:**
- The pairs are: BT, EQ, HN.
- The first letters are: B, E, H.
- The second letters are: T, Q, N.

2. **Determine the Position of Each Letter in the Alphabet:**
- B = 2
- E = 5
- H = 8
- T = 20
- Q = 17
- N = 14

3. **Analyze the First Letters:**
- The first letters are B (2), E (5), H (8).
- The difference between the positions:
- E - B = 5 - 2 = 3
- H - E = 8 - 5 = 3
- The pattern shows that we are adding 3 to the position of the first letter.
- Next letter: H (8) + 3 = 11, which corresponds to K.

4. **Analyze the Second Letters:**
- The second letters are T (20), Q (17), N (14).
- The difference between the positions:
- Q - T = 17 - 20 = -3
- N - Q = 14 - 17 = -3
- The pattern shows that we are subtracting 3 from the position of the second letter.
- Next letter: N (14) - 3 = 11, which also corresponds to K.

5. **Combine the Results:**
- The next letter-pair in the series is KK.

### Final Answer:
KK