The correct answer is Guglielmo Marconi, an Italian inventor.
Marconi developed practical systems for sending and receiving radio signals over long distances in the late 1890s and early 1900s. In 1901, he achieved the first transatlantic radio transmission, sending a signal across the Atlantic Ocean.
For his work on wireless telegraphy, Marconi shared the Nobel Prize in Physics in 1909 with Karl Ferdinand Braun. He is widely credited as the inventor of radio in most exam answer keys, though earlier scientific groundwork was laid by others such as Jagadish Chandra Bose and Nikola Tesla.