The commonest type of cataract is –

You must be thinking, why not a blue dot? Carefully read the question. Here the question is about the commonest type of cataract (not congenital cataract). A most common type of cataract is senile cataract (Age-related cataract). A most common type of senile cataract is cuneiform cataract (70%). "In general, the predominant form can be given as cuneiform (70%), nuclear (25%), and cupuliform (5%)". — Anatomy & Physiology of eye "Cortical senile (Cuneiform) cataract is the most common form of senile cataract prevalent in aging population".