the energy carried by a photon is equal to
(planck's konstant) times (the frequency of the photon) .
planck's konstant is 6.626 x 10⁻³⁴ m²-kg/s (rounded)
the answer is a. concurrent.
since the boot-print was left there nearly 50 years ago, there has been very little wind and very little rain in that area, and plus, there have been very few people or other animals walking around in that spot to disturb it.