Who is credited for developing the wave theory of electromagnetism?

James Clerk Maxwell

Explanation:

James Clerk Maxwell was the scientific who presented for the first time, electricity, magnetism and light as different manifestations of the same phenomenon. In fact, for this unification considered a scientific milestone in its time (between the 1860s and 1870s), Maxwell is recognized as one of the greatest scientists of the nineteenth century.

Maxwell, who was Scottish, realized that electric fields and magnetic fields can join together to form electromagnetic waves (which in turn had connection to light). So, he summed up this relationship between electricity and magnetism to develop his theory in four equations that now are known as "Maxwell's Equations".

think its the third option