Cho \({u_n} = \dfrac{{{n^2} - 3n}}{{1 - 4{n^3}}}\)...

Câu hỏi: Cho \({u_n} = \dfrac{{{n^2} - 3n}}{{1 - 4{n^3}}}\).  Khi đó \(\lim {u_n}\)bằng?

A. 0

B. \( - \dfrac{1}{4}.\)

C. \(\dfrac{3}{4}.\)

D. \(-\dfrac{3}{4}.\)