The correct option is A a1,a2,a3.....are in A.P.
In=(xn+1n+1tan−1x)10−∫10xn+1n+1.11+x2dx(n+1)In=π4−∫10xn+11+x2dx(n+3)In+2=π4−∫10xn+31+x2dx∴(n+1)In+(n+3)In+2=π2−1n+2∴an=(n+3)⇒a1,a2,a3.....are in A.P.
bn=(n+1)⇒b1,b2..... are in A.P.
cn=π2−1n+2 not in any progression.