The accepted model of the atom was changed.
Think it is b
but i am not sure at all
Answer:

Explanation:
The empirical formula is the simplest whole-number ratio of the elements in a compound to one another. To find the empirical formula given a molecular formula, divide all the subscripts by their greatest common factor.
3, 12, and 6 can all be divided by 3, which makes the empirical formula 
Answer : The density of air in
and
is,
and
respectively.
Explanation :

where,
P = pressure of air = 1 atm
V = volume of air
T = temperature of air = 297 K
The conversion used for the temperature from Fahrenheit to degree Celsius is:


The conversion used for the temperature from degree Celsius to Kelvin is:


n = number of moles
m = mass of air
M = average molar mass of air = 28.97 g/mole
= density of air = ?
R = gas constant = 0.0821 L.atm/mol.K
Now put all the given values in the above formula, we get:



Now we have to calculate density in
.
Conversion used :

So,

The density of air in
is, 
Now we have to calculate density in
.
Conversion used :

So,

The density of air in
is, 