Arc-ed up

Geometry

$\large \arcsin 1 + \arccos 1 + \arctan 1 + \text{arccot} \, 1 + \text{arcsec} \, 1 + \text{arccsc} \,1 = \ ?$

0

\dfrac{\pi}{4}

\dfrac{\pi}{2}

\dfrac{3\pi}{4}

\pi

\dfrac{5\pi}{4}

\dfrac{3\pi}{2}

\dfrac{7\pi}{4}