Answer:
The G-note's wavelength is longer.
Step-by-step explanation:
As we know that 
The relationship between frequency, wavelength and the speed given as 
Speed = Frequency x Wavelength 
V= f λ 
For constant speed, if wavelength increase then the frequency of the sound get reduce. 
The wavelength of the A-note sound waves is smaller than the G -notes sound waves.
Therefore the answer of the given question will be A.