DEEZ NUTS ha gattti -sorry
I suggest you to go with C !! it is absolutely wrong sentence !!
increasing the gas particles will increase the collision between them so !!
your answer is C !!
You multiply avogadro's number to what you were given.
8.30x10^23 * 6. 0221409x10^23
=1.357*10^25
That should be the right answer but I'm not sure. It has been awhile since I have done this.
Answer : The wavelength is 
Solution : Given,
frequency = 29.2 Hz
Formula used :

where,
= frequency
= wavelength
c = speed of light = 
Now put all the given values in this formula, we get the wavelength.

Therefore, the wavelength is 
The answer is b because if you’re fan is blowing and you spend it the opposite way, the air will be cooler