10 years a go the average age of all the 25 teachers of the girls college was 45 years. 4 years a go the principal has retired from her post at the age of 60 year. So after one year a new principal whose age was 54 years recruited from outside . The present average age of all the teachers is if principal is also considered as a teacher:

Options

A. 54(18/25)years
B. 55(17/25) years
C. 49(1/2) years
D. none of these

Answer

A