Final answer:
The two scientists who invented the telegraph after Samuel Morse but published it earlier were Elisha Gray and Alfred Vail, making the correct answer c). Samuel Morse is best known for Morse Code, and Guglielmo Marconi is credited with the invention of the radio.
Step-by-step explanation:
The two scientists who are credited with the invention of the telegraph after Samuel Morse but published it earlier were Elisha Gray and Alfred Vail. Therefore, the correct answer to the question is c) Elisha Gray and Alfred Vail. While Samuel Morse is widely recognized for his contribution to the development of the telegraph and the creation of Morse Code, the telegraph itself went through various developments with multiple contributors. Ultimately, Morse's version and the Morse Code became the most widely used and recognized systems of telegraph communication during that time.
With regard to the invention of the radio, the credit is often attributed to Guglielmo Marconi, who successfully transmitted signals across the Atlantic Ocean and founded the Marconi Wireless Telegraph Company. Similarly, the telephone, although patented by Alexander Graham Bell, was improved upon by others including Thomas Edison, whose version resembled the modern telephone we know today. These advancements in communication technologies drastically changed the landscape of information exchange and business communications across the globe.