The quantity of seepage of water through soils is proportional to

ANS:D - both (a) and (b).

We know that;

Seepage,
Q=kH(Nf/Nd)

where,
k = coefficient of permeability of the soil
H = Total head loss through the soil
Nf = number of flow channels
Nd = number of equipotential drops.

Therefore, seepage quantity is proportional to both coefficients of permeability of the soil and total head loss through the soil. Q = kiA.
i = h/l.

Hence,
Q directly proportional to k.
Q directly proportional to h.