Details pertaining to an orthogonal mental cutting process are given below.

$\begin{array}{ll} \text{Chip thickness ratio} & 0.4 \\ \text{Undeformed thickness} & 0.6 \text{ mm} \\ \text{Rake angle} & +10^{\circ} \\ \text{Cutting speed} & 2.5 \text{ m/s} \\ \text{Mean thickness of primary shear zone} & 25 \text{ microns} \end{array}$

The shear strain rate in $s^{-1}$ during the process is

1. $0.1781 \times 10^5$
2. $0.7754 \times 10^5$
3. $1.0104 \times 10^5$
4. $4.397 \times 10^5$