A letter series is given with one term missing. Choose the correct alternative that will complete the series: BC, GHI, NOPQ, ?

Introduction / Context:
This reasoning question presents a series of letter groups in the English alphabet and asks you to identify the next term. Such series questions test pattern recognition, understanding of alphabetical positions, and the ability to generalise a rule from a few examples. Here, both the length of each term and the starting letter are changing in a systematic way.

Given Data / Assumptions:

• The given series is: BC, GHI, NOPQ, ?• Each term is a sequence of consecutive letters.• The number of letters in each term increases as we move forward.• We assume that the alphabet cycles from Z back to A if needed.

Concept / Approach:
To solve this type of series, we examine two aspects. First, we look at how many letters each term contains. Second, we see how the starting letter of each term moves through the alphabet. The increasing lengths suggest a pattern in the number of letters, while the jump in starting letters reveals a separate numeric sequence. Combining both gives the correct missing term. If a term needs letters beyond Z, the series continues by wrapping around to A.

Step-by-Step Solution:
Step 1: Count the letters in each term: BC has 2 letters, GHI has 3, and NOPQ has 4. The lengths follow the pattern 2, 3, 4, so the next term must have 5 letters.Step 2: Look at the starting letters and their positions in the alphabet. B is 2, G is 7, N is 14.Step 3: Note the jumps between these positions. From 2 to 7 the increase is 5, and from 7 to 14 the increase is 7. The differences themselves follow an odd number pattern, increasing by 2 each time.Step 4: The next increase should be 9. Add 9 to 14, giving 23, which corresponds to the letter W.Step 5: Since the next term must contain 5 consecutive letters starting from W, we write W, X, Y, Z, and then wrap to A.Step 6: This produces the group WXYZA, which matches option C.

Verification / Alternative check:
Check that the pattern holds for every term. The first term starts at B and has 2 letters. The second starts at G (5 letters ahead) and has 3 letters. The third starts at N (7 letters ahead from G) and has 4 letters. Our proposed fourth term starts at W (9 letters ahead from N) and has 5 letters. Both the increasing starting letter jumps and the increasing lengths are consistent. No other option in the list both begins at the correct letter and contains exactly 5 consecutive letters with correct wrap around at Z.

Why Other Options Are Wrong:
BCDEF has 5 letters but restarts from B and ruins the increasing jump pattern. UVWXY begins at U, which does not match the calculated starting letter W and also fails the jump sequence. WXYZA is the only option that begins at W and has 5 consecutive letters, including the wrap back to A. STUVW begins at S and therefore also does not satisfy the numeric pattern of starting letters.

Common Pitfalls:
Many learners look only at the number of letters in each term and ignore how the starting letters move. Others may not consider wrap around from Z to A and get stuck. A reliable method is always to convert letters to their numeric positions, look for arithmetic patterns in the differences, and also verify the length pattern. Taking both aspects together makes the correct answer clear and avoids random guessing.

Final Answer:
The missing term in the series is WXYZA.