$[6](25$ points$)$ The hydraulic conductivity of the soil is $3\mathrm{.}2{10}^{-6}\frac{m}{s},$ the saturated unit weight of soil is $20k\frac{N}{m^3}.$ Use the flow net shown below $($Note: datum already specified in the figure$)$ to determine:

$($a$)$ Flow rate

$($b$)$ Total head at point A

$($c$)$ Pore water pressure at point A

$($d$)$ Efective vertical stress at pour $A$

$($e$)$ Factor of safety of exit gradient aguinst quicksand condition