As of 2013 pit latrines are used by an estimated ____________ people.
(a) 1.77 billion
(b) 2.77 million
(c) 1.77 billion
(d) 4.66 billion
This question was posed to me in final exam.
My doubt stems from Design of Septic Tanks topic in section Road Estimating, Sanitary and Water Supply Work of Civil Engineering Drawing