There is too much information given, it's hard to understand exactly which variables are important in this problem.
Hey there,
Your question states: What factors affect the speed of water waves
Let's get one thing out the way, (wavelength) does

affect the the speed of water. If anything, it would be how high the wavelength's are. The higher the wavelengths are, the more that it would affect the speed, because there very high, but if it were to go longer on the width side, that would increase the speed, but that's not the case. Your correct answer would be (higher wavelength).
Hope this really helps you.
Cosmic background radiation is electromagnetic radiation from the sky with no discernible source. The origin of this radiation depends on the region of the spectrum that is observed.