The correct answer is:
b. J.J. Thomson
Explanation:
1. J.J. Thomson is credited with the discovery of the electron through his experiments with cathode rays.
2. In 1897, Thomson conducted experiments that led him to propose the existence of negatively charged particles within atoms, which he called electrons.
3. His discovery revolutionized the understanding of atomic structure and laid the foundation for modern atomic theory.
4. James Maxwell is known for his contributions to the field of electromagnetism, but he did not discover the electron.
5. William Crookes, on the other hand, made significant contributions to the understanding of vacuum tubes and cathode rays, but he did not discover the electron either.
6. Therefore, the correct scientist who discovered the electron among the options provided is J.J. Thomson.
