Cho dãy số (un) được xác định bởi \({u_1} = 2017,{u_n} = {u_{n - 1}} + \frac{1}{{A_n^2}},\left( {n = 2,3,4...} \right)\).

A. \({u_{2018}} = \frac{{2016.2018}}{{2017}}.\)

B. \({u_{2018}} = \frac{{2017.2019}}{{2020}}.\)

C. \({u_{2018}} = \frac{{2017.2018}}{{2019}}.\)

D. \({u_{2018}} = \frac{{2017.2019}}{{2018}}.\)