Average age of A, B and C is 84 years. When D joins them the average age becomes 80 years. A new person E, whose age is 4 years more than D, replaces A and the Average of B, C, D and E becomes 78 years . What is the age of A ?

• A. 60 years.
• B. 70 years
• C. 80 years
• D. 50 years