Malignant change in nevus is characterised by-a)  Darkeningb)  Hemorrhagec)  Itchingd)  Increase in Size
Warning size of melanoma are : -

Itching or pain in a pre-existing mole.
Enlargement of a pre-existign lesion.
Irregularity of the borders of a pigmented lesion.
Variegation of color within a pigmented lesion.
Assymetry of lesions.
ab
cd
bd
ac