Six letters, M, N, O, P, Q, and R are written on different faces of a dice. Three positions of this dice are shown here. Find the letter on the face opposite of 'N'.

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​​Logic: According to the dice rule, if two or three positions of the same dice are given with one common face but in different orientations, then to find the opposite pairs of faces, rotate in the clockwise direction from the common face.

So, now let's consider the first and third positions of the dice.

Thus, the opposite faces are (O$$\iff$$P); (Q$$\iff$$R); (N$$\iff$$M)

Therefore, the opposite face of 'N' is 'M'.

So, the correct answer is option (a).