The answer is D
Explanation:
Answer: The 1st one is B. I'm pretty sure the 2nd one is A. and the 3rd one is D.
Explanation: I hope this helped, although I'm not sure for the second one
To solve the exercise it is necessary to take into account the concepts of wavelength as a function of speed.
From the definition we know that the wavelength is described under the equation,

Where,
c = Speed of light (vacuum)
f = frequency
Our values are,


Replacing we have,



<em>Therefore the wavelength of this wave is
</em>
Answer:
a
Explanation:
water is only able to desolve two substances , salt , sugar,