Problem: Which political figure was best man at the 1927 second wedding of Italian inventor Guglielmo Marconi?
Answer: benito mussolini

Problem: What country was formerly known as Formosa?
Answer: taiwan

Problem: In 1915, which Balkan nation joined W.W.I., on the side of the Central Powers (i.e. Germany), by declaring war on Serbia?
Answer: bulgaria

Problem: What was visited by Viking, Pathfinder, and Curiosity?
Answer:
mars