In the sketch of stomatal apparatus given alongside, the parts I, II, III and IV were labelled differently by four students. The correct labelling is shown in :
(1) (I) guard cells, (II) stoma, (III) starch granule, (IV) nucleus
(2) (I) cytoplasm, (II) nucleus, (III) stoma, (IV) chloroplast
(3) (I) guard cells, (II) starch, (III) nucleus, (IV) stoma
(4) (I) cytoplasm, (II) chloroplast, (III) stoma, (IV) nucleus