In question figure, a triangle in the middle is divided into four parts, out of which two parts are shaded. In that triangle, the upper left part and bottom right partis shaded. Thus, in answer figure, in that triangle upper right part and bottom leftpart should be shaded. Therefore, option 2 and 3 gets eliminated. In option 4 image is inverted. Since the mirror is placed at the left of the question figure, the answer image cannot be inverted. Therefore option 4 gets eliminated.
Hence, the figure in option 1 is the correct answer.