The runoff coefficient to be used in the Rational Method equation for a storm sewer drainage area with residential lots of $\frac{1}{3}$ acre, having deep sand soil and less than $2\%$ surface slope is:

a$.0\mathrm{.}22$

b$.0\mathrm{.}25$

c$.0\mathrm{.}28$

d$.0\mathrm{.}30$