The most abundant elements by mass 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. `15 kg`
B. `37.5 kg`
C. `7.5 kg`
D. `10 kg`
