the average age of class of 23 students is 19 years . After a week , 7 students , whose average age is 21 years , joined the class . Later 3 students , whose Average age is 18 years , moved to another class . what is the current Average age of class ?

A ) 19.6 years B) 18.5 Years C ) 20.1 years D ) 20.6years