C.figure 3 is the answer had the same and got is right
The energy of a photon is given by:

where h is the Planck constant and f is the photon frequency.
We know the energy of the photon,

, so we can rearrange the equation to calculate the frequency of the photon:

And now we can use the following relationship between frequency f, wavelength

and speed of light c to find the wavelength of the photon:
Answer:
d₂ = 1.466 m
Explanation:
In this case we must use the rotational equilibrium equations
Στ = 0
τ = F r
we must set a reference system, we use with origin at the easel B and an axis parallel to the plank
, we will use that the counterclockwise ratio is positive
+ W d₁ - w_cat d₂ = 0
d₂ = W / w d₁
d₂ = M /m d₁
d₂ = 5.00 /2.9 0.850
d₂ = 1.466 m