We are shown 5 different waves.
Q. 1: Which wave has the largest wavelength?
Recall that the wavelength is the distance between identical points (adjacent crests or troughs)
As you can see, wave E has the largest distance between the two crests.
Hence, wave E has the largest wavelength.
Q. 2: Which two waves have the same wavelength?
As you can see, wave A and B have the same wavelength.
Q. 3: Which wave has the highest frequency?
Higher frequency means that the wave completes more cycles in a shorter time period.
As you can see, wave C has the highest frequency.
Q.4: Which wave is likely carrying the least amount of energy?
The energy depends upon the amplitude and frequency of the wave.
Wave B has the smallest amplitude and low frequency.
For the given case, wave B is likely carrying the least amount of energy.