Plz fast

​Q68. If a₁, a₂, a₃, ...... a_{2n +1} are in A.P. then $\frac{a_{2n+1}-a_1}{a_{2n+1}+a_1}+\frac{a_{2n}-a_2}{a_{2n}+a_2}+.....+\frac{a_{n+2 }-a_n}{a_{n+2}+a_n}$ is equal to :


      (1) $\frac{n\left(n+1\right)}{2}.\frac{a_2 -a_1}{a_{n+1}}$


      (2) $\frac{\mathrm{n}\left(\mathrm{n} +1\right)}{2}$


      (3) (n + 1) (a₂ – a₁)


      (4) None of these 


      (4) None of these