The correct answer is option 4 - Electromagnetic radiations.

X-rays are a form of electromagnetic radiation. Electromagnetic radiation is a type of energy that travels through space in the form of waves. It consists of oscillating electric and magnetic fields perpendicular to each other.

Option 1 - Electrons only: This option is incorrect. While electrons are involved in the production of X-rays in X-ray machines, they are not the constituent particles of X-rays. X-rays are generated when high-energy electrons strike a target material.

Option 2 - Protons only: This option is incorrect. Protons are not involved in the production of X-rays. They are found within the atomic nucleus and have a positive charge.

Option 3 - Neutrons only: This option is incorrect. Neutrons are not involved in the production of X-rays. Neutrons are also found within the atomic nucleus but have no charge.

X-rays have a wide range of applications, including medical imaging, security scanning, and material testing. They have a higher energy and shorter wavelength than visible light, allowing them to penetrate through materials such as skin and soft tissues.