L, M, N, O and P are standing in a straight line facing east. N is standing at the north end of the line and O is standing at the south end. L and M are standing together, and P is a neighbour of both M and N. Who is standing third from the north end?

Introduction / Context:
This is a basic linear arrangement question combined with directional labels for the two ends of the line. The participants are placed in a straight line, and the task is to use the given adjacency and end position conditions to determine the exact order and then identify who is third from the north end. Such arrangement questions are common in reasoning tests and reward careful use of constraints rather than guesswork.

Given Data / Assumptions:

• Five people L, M, N, O and P are standing in a line facing east.
• N is standing at the north end of the line.
• O is standing at the south end of the line.
• L and M are together, meaning they stand in consecutive positions.
• P is a neighbour of both M and N.
• The positions are arranged from north end at the top to south end at the bottom.

Concept / Approach:
We treat the line as a vertical arrangement with positions numbered from 1 (north end) to 5 (south end). N must occupy the first position and O must occupy the fifth position. The conditions that L and M sit together and that P is neighbour of both M and N severely limit the possible placements. We systematically test positions consistent with all clues and then read off who sits in the required position counting from the north end.

Step-by-Step Solution:
Step 1: Since N is at the north end, N must be in position 1.Step 2: Since O is at the south end, O must be in position 5.Step 3: P is neighbour of N, which is in position 1, so P must be in position 2 because that is the only adjacent position.Step 4: P is also neighbour of M. If P is in position 2, M must occupy position 3, the only remaining position adjacent to position 2.Step 5: L and M must be together. With M already fixed at position 3, L must be in position 4 in order to be adjacent to M.Step 6: The complete order from north end to south end is now N, P, M, L, O. Counting from the north end, the third position is occupied by M.

Verification / Alternative check:
Once the arrangement N, P, M, L, O is found, we can quickly verify all statements. N is at the north end and O at the south end. L and M are in consecutive positions (3 and 4). P is adjacent to both N and M because it stands between them in position 2. No other arrangement satisfies all conditions at once, so this order is unique and confirms that M is indeed third from the north end.

Why Other Options Are Wrong:
Option A (L) corresponds to the fourth position from the north, not the third. Option B (O) is at the south end, which is position five. Option D (P) is in the second position from the north. Only option C correctly matches the person in the third position from the north end, namely M.

Common Pitfalls:
A typical mistake is to misinterpret the phrases north end and south end as directions facing rather than as labels for the ends of the line. Another error occurs when students try to place L and M first and later attempt to adjust the arrangement, which can violate the requirement that P must be neighbour of both M and N. A clean approach is always to place the end points first, apply the neighbour conditions step by step and only then check remaining positions.

Final Answer:
The person standing third from the north end is M, so the correct option is “M”.