Why Do Class Systems Retain Some Caste-Like Qualities (Such as the Inheritance

Why do class systems retain some caste-like qualities (such as the inheritance of wealth) , rather than becoming complete meritocracies?

A) A pure meritocracy would eliminate families and reduce social order.
B) Some caste elements increase social mobility.
C) Too many people would be poor if inequality were based only on merit.
D) Keeping some caste qualities increases a society's productivity.