Tính: lim(1/(1.3)+1/(3.5)+....+1/(2n-1)(2n+1))

A) lim(1/(1.3)+1/(3.5)+....+1/(2n-1)(2n+1))
B) lim(1/(1.3)+1/(2.4)+....+1/n(n+2))
C) lim(1- 1/2^2)(1- 1/3^2)....(1-1/n^2)
D) lim (1/1.2+1/2.3+....+1/n(n+1))