Ultimate BOD of a river water sample is $20 \mathrm{mg} /$ L. BOD rate constant (natural log) is 0.15 day $^{-1}$. The respective values of $\mathrm{BOD}$ (in $\%)$ exerted and remaining after 7 days are:
(A) 45 and 55
(B) 55 and 45
(C) 65 and 35
(D) 75 and 25
Ultimate BOD of a river water sample is $20 \mathrm{mg} /$ L. BOD rate constant (natural log) is 0.15 day $^{-1}$. The respective values of $\mathrm{BOD}$ (in $\%)$ exerted and remaining after 7 days are:
(A) 45 and 55
(B) 55 and 45
(C) 65 and 35
(D) 75 and 25