Final answer:
Adolphe Sax is the inventor of the saxophone, which is also slang for the instrument itself. The invention of the radio is attributed to Guglielmo Marconi. Option a is the correct answer.
Step-by-step explanation:
The 3-letter surname of the Belgian instrument maker Adolphe is Sax, which is also slang for his greatest invention, the saxophone. Regarding the invention of the radio, the correct answer is c. Guglielmo Marconi.
Although there were many contributors to the development of radio technology, Marconi is often credited with being the first to successfully achieve long-distance wireless transmission.
So option a is the correct answer among the given option.