I thinks it's B. Molecular Receptor, but I am not sure.
Answer - Theory
Reasoning - Your best bet and term to describe the evolution by natural selection is theory as to still scientific theory/research is still ongoing and changes can be made in a different direction.
To calculate this we will use the light equation:

λ

We have Frequency

.
We know that speed of light in vacuum is

.
Since a unit of speed of light is m/s, we can change the unit of frequency Hz to 1/s, since Hz means cycles per second (f=1/T).
So:

<span>

</span>
<span>

λ

</span>⇒ λ

⇒ λ

⇒ <span>λ</span>