Find the missing group:
EFG, HIJ, LMN, ?

The correct option is QRS.

To find the missing group in the series EFG, HIJ, LMN, ?, let us analyze the pattern established between the letter groups:

Step 1: Internal pattern within each group
Each group consists of three consecutive letters of the alphabet:
• EFG (E, F, G)
• HIJ (H, I, J)
• LMN (L, M, N)

Step 2: Transition pattern between groups
Let us observe how the last letter of one group leads to the first letter of the next group:
• From EFG to HIJ: The group ends with G and the next begins immediately with H (0 letters skipped).
• From HIJ to LMN: The group ends with J and the next begins with L (1 letter, K, is skipped).

Following this increasing pattern of skipped letters (0, 1, 2...):
• From LMN to the next group: The group ends with N, so we must skip 2 letters (O and P).
• Skipping O and P brings us to the letter Q.

Step 3: Forming the final group
Starting with Q and taking 3 consecutive letters gives us:
$\text{Q}\to \text{R}\to \text{S}$

Therefore, the missing group is QRS.