Please help !!!

A cash flow at time zero (now) of $8, 475 is equivalent to another cash flow that is a uniform series with EOY annuity of $2, 400 with the interest rate of 5% per year. The duration of this equivalent cash flow was closest to (a) 2 yr (b) 2.5 yr (c) 3 yr (d) 3.5 yr (e) 4 yr (f) Not enough information given