The most abundant elements by mas in the body of a healthy human adult are Oxygen `(61.4%)`, Carbon `(22.9%)`. Hydrogen `(10.0)%)`, and Nitrogen `(2.6%)`. The weight which a `75 kg` person would gain if all `.^(1)H` atoms are replaced by `.^(2)H` atoms is
A. 37.5 kg
B. 7.5 kg
C. 10 kg
D. 15 kg
