Answer:

(b) is the correct answer.

Explanation:

Options (a) and (b) gives the displacement along the positive direction of x-axis. That is, the man moves from negative to positive direction.

He was initially at a negative position in both these options and moves towards the positive direction of x-axis which REFERS to positive displacement.

But in the coordinates given in (b) we can see that he was initially at a positive position and moves towards the left of the x-axis to reach a negative position.

In 2D for x-axis anything that moves from left to right irrespective of their initial or final sign can be called positive displacement, whereas if it moves from right to left it is called negative displacement.

If you are confused by this method of observation, you can use the following method to find the answer:

Displacement = (Final position - Initial Position)

Here the final and initial values in the bracket must be given their respective signs during the calculation. If you get the final answer of displacement as positive then it is positive displacement and if it is negative then the displacement is negative.

For example:

Lets TAKE the option (a) (-8m , 7m)

         Displacement = [ 7 - (-8)]

                                 = [ 7 + 8 ]

                                 = 8   (which is positive)

     for option (b) (7m , -3m)

         Displacement = [ (-3) - 7]

                                 = -10  (which is negative)

I explained it this much so that you would understand the CONCEPT and not just write the answer for this single question but all questions from this topic.

Hope this really helps you and sorry for being so lengthy.