$**$Question:$**$

In civil engineering, the ultimate bearing capacity of a foundation on cohesionless soils primarily depends on:

$**$a$)$ Shear strength of the soil$**$

$**$b$)$ Cohesion of the soil$**$

$**$c$)$ Frictional resistance of the soil$**$

$**$d$)$ Plasticity index of the soil$**$