The shear strength of clay is given by the Mohr-Coulomb equation:
\[
\tau = c + \sigma \cdot \tan(\phi)
\]
Where:
- \( \tau \) = shear strength
- \( c \) = cohesion
- \( \sigma \) = normal stress
- \( \phi \) = angle of shearing resistance
Given:
- \( c = 80 \, \text{kPa} \)
- \( \phi = 10^\circ \)
- \( \sigma = 100 \, \text{kPa} \)
Now, we calculate the shear strength:
\[
\tau = 80 + 100 \cdot \tan(10^\circ)
\]
\[
\tau = 80 + 100 \cdot 0.1763
\]
\[
\tau = 80 + 17.63 = 97.63 \, \text{kPa}
\]
Step 2: Conclusion.
Thus, the correct answer is 97.63 kP(A)
Final Answer:
\[
\boxed{97.63 \, \text{kPa}}
\]