Correct expression for density of an ideal gas mixture of two gases 1 and 2, where `m_(1)` and `m_(2)` are masses and `n_(1)` and `n_(2)` are moles and `M_(1)` and `M_(2)` are molar masses.
A. `d=((m_(1)+m_(2)))/((M_(1)+M_(2)))`
B. `d=((m_(1)+m_(2)))/((n_(1)+n_(2)))(P)/(RT)`
C. `d=((n_(1)+n_(2)))/((m_(1)+m_(2)))xx(P)/(RT)`
D. None of these