Matter waves are:
A. Electromagnetic waves
B. Matter waves
C. Either mechanical or electromagnetic
D. Neither mechanical nor electromagnetic

Hint: It is a wave related to particles revolving in an atom around the nucleus. De Broglie named these waves as matter waves or De Broglie's waves. Its wavelength is calculated from
wavelength \[\lambda = \dfrac{h}{{mv}}\],
where h is planck constant. This theory mainly conveys the wave nature of light having energy given by plank E=h$\upsilon $. ($\upsilon $ is frequency of radiation). These waves do not require any material medium for its propagation. It is coming in mainly non relativistic theory.

Complete step by step answer:
Now moving to the question,
Matter waves are not like electromagnetic waves and mechanical waves. Electromagnetic waves have larger wavelengths as compared to matter waves, also matter waves don’t exist in vacuum. Matter waves depict the wave nature of matter.
Therefore option D. is the correct option.

Note:
Electromagnetic waves also are referred to as EM waves that are produced when an electrical field comes in touch with the magnetic flux. It can also be said that electromagnetic waves are the composition of oscillating electric and magnetic fields.
Applications of Electromagnetic Waves
Following are a few applications of electromagnetic waves:
1. Electromagnetic waves can transmit energy in vacuum or using no medium in the least.
2. Electromagnetic waves play a crucial role in communication technology.
3. Electromagnetic waves are used in RADAR
4. UV rays are wont to detect forged bank notes. Real banknotes don’t turn fluorescent under the UV light.
5. Infrared radiation is used for night vision and is used in security cameras.