For the construction of a highway, a cut is to be made as shown in the figure.

The soil exhibits $c’=20$ kPa, $\phi’=18^{\circ}$, and the undrained shear strength $=80$ kPa. The unit weight of water is $9.81 kN/m^3$. The unit weights of the soil above and below the ground water table are $18$ and $20 \: kN/m^3$, respectively. If the shear stress at point $A$ is $50$ kPa, the factors of safety against the shear failure at this point, considering the undrained and drained conditions, respectively, would be

- $1.6$ and $0.9$
- $0.9$ and $1.6$
- $0.6$ and $1.2$
- $1.2$ and $0.6$