The correct option is B π12
Let I=5π/24∫π/24dx(1+3√tan2x)
⇒I=5π/24∫π/243√cos2x3√sin2x+3√cos2x dx ⋯(1)
Using property : b∫af(x) dx=b∫af(a+b−x) dx
I=5π/24∫π/243√sin2x3√sin2x+3√cos2x dx ⋯(2)
Adding (1) and (2), we get
2I=5π/24∫π/243√sin2x+3√cos2x3√sin2x+3√cos2x dx
⇒2I=5π/24∫π/241 dx
⇒2I=5π24−π24
∴I=π12