A rectangular foundation $4$ m by $6$ m $($Figure below$)$ transmits a stress of $100$ kPa on the surface of a soil deposit.Plot the distribution of increases of vertical stresses with depth under points A$,$ B$,$ and C up to a depth of $20$ m$.$ Atwhat depth is the increase in vertical stress below A less than $10\%$ of the surface stress?m$-4$ mB$-2$ m$2$ m