The results of a consolidated drained triaxial test on a normally consolidated clay are shown in the figure. The angle of internal friction
$\sin ^{-1}\left(\frac{1}{2}\right)$
$\sin ^{-1}\left(\frac{1}{3}\right)$
- $\sin ^{-1}\left(\frac{2}{3}\right)$
- $\sin ^{-1}\left(\frac{3}{4}\right)$
