Ravi followed the following procedure for staining the temporary mount of leaf peel on the slide.
(i) To put a single drop of stain on leaf peel and wash it with water.
(ii) Cover the leaf peel withcover slip.
(iii) To put a single drop of glycerine on leaf peel.
(iv) Observe the slide undermicroscope. But the steps are not in order . What should be the correct sequence?