Which photons are the highest energy?

In visible spectrum of light, the frequency increases from red to violet. In other words, the frequency of violet light is higher than that of red light or that of blue-green light.

The energy of a photon is directly proportional to its frequency. Therefore, the violet light has the highest energy.

...... The answer is d.

It's d.

d

d. violet

That has the highest energy of the options given but there are more energetic photons such as x-ray and gamma ray.

For photons:
more energy = shorter wavelength.

https://en.wikipedia.org/wiki/Visible_spectrum#Spectral_colors