Answer
(e)
Work Step by Step
The daily manure production is $$700\text{
cows}\times 40\text{ L/cow/day}=28000\text{
L/day}.$$
The total manure for $30$ days will be $$28000\text{
L/day}\times 30\text{ days}=840000\text{ L}.$$ The answer is (e).
