The correct answer is C. Kao and Hockham.
Clad waveguide structure is a type of waveguide that is used to guide electromagnetic waves. It consists of a central core surrounded by a cladding layer. The core and cladding layers are made of different materials with different refractive indices. The refractive index of the core is higher than the refractive index of the cladding. This difference in refractive indices causes the electromagnetic waves to be guided along the core.
Kao and Hockham proposed the use of clad waveguide structure in 1966. They showed that clad waveguide structure could be used to transmit light over long distances without loss. This discovery led to the development of optical fiber communication systems.
Edward Appleton was a British physicist who made significant contributions to the study of the ionosphere. He was awarded the Nobel Prize in Physics in 1947 for his work on the ionosphere.
Schriever was an American general who played a key role in the development of the intercontinental ballistic missile (ICBM). He was also the first director of the National Reconnaissance Office.
James Maxwell was a Scottish physicist and mathematician who is considered to be one of the founders of modern physics. He is best known for his work on electromagnetism, which led to the development of Maxwell’s equations.