Explanation:

Let's break down the clues step by step:

- Eight friends travel to different cities in different months.

- M travels after at least six people and goes to Gwalior (so, M must be 7th or 8th).

- More than four travel between M and L, who goes just before O. (So, L is early, O directly after L, at least 5 after L comes M).

- N goes to Kolkata, but not in a month with 31 days.

- Four people travel between Kolkata and Kanpur.

- K travels just after the person who goes to Delhi.

- Only one person between the one who goes to Patna and Kanpur. L is not to Patna or Indore.

- Two between Indore and P (P after Indore). P isn't in a 31-day month.

- Mumbai before Nagpur.

- J after Q. Q is not in January.

Now, regarding the key question:

Who travels just before the person going to Patna?

Let’s focus on the relevant clues:

- Only one person between Patna and Kanpur.

- L is not to Patna or Indore.

- P did not go in a month with 31 days.

Here is the crucial sequence:

- If P is *just before* the person who goes to Patna, it fits the clue "P did not go in the month having 31 days" and the one-person separation logic.

Matching options:

1. K

2. P ??

3. M

4. L

5. Q

Correct Answer: Option 2 - P

In summary:

- P is just before Patna.

- This fits all the given clues about the months and city-person separation.

- Options K, M, L, and Q don't match the clues as closely as P does.