Of 100,000 Customers Who Were Active in the Year 2005

Multiple Choice

Of 100,000 customers who were active in the year 2005, only 60,000 are still active in 2006. What would the average retention rate be?

A) It cannot be determined because the initial 100,000 have not been segmented into cohorts.
B) 0.4
C) 0.54
D) 0.6
E) None of the above