Trupti was observing an onion peel stained with safranin under a microscope. The colour of the cell wall was
Pinkish red
Safranin is used as a biological stain and it helps in the detection of cellulose, mucin, mast cells, etc. The cell wall of plants contains cellulose. Hence, safranin will stain the cellulose of cell walls making it appear pinkish red.