NaOH but you didnt give options
solution:
You need to find the frequency, and they have already given you the wavelength. And since you already know the speed of light, you can use formula (2) to answer this problem. Remember to convert the nano meters to meters because the speed of light is in meters. 

Answer: B, Al, Ga, In, Tl
Explanation:
The flow rate of water differs from honey due to the texture and thickness of the product. Honey’s thickness doesn’t allow it to move as quickly as the water, therefore affecting the flow rate.