Final answer:
The mathematical center of the world in the 4th century BC was Alexandria, due to the presence of the Museon, or Museum of Alexandria, which was a hub for learning and the largest library at the time.
Step-by-step explanation:
The mathematical center of the world in the 4th century BC was Alexandria, as it was the site of the Museon, often referred to as the Museum of Alexandria. This institution was more than just a museum; it was a major center of learning and housed the world's largest library, with a collection of approximately 700,000 scrolls. This hub of intellectual activity is where famed scholars like Eratosthenes conducted scientific research and where important mathematical discoveries and studies were made.
During the Hellenistic period, Alexandria was the largest Greek city and the capital of the Ptolemaic kingdom. It boasted a population of about one million people, making it not just a significant cultural center but also a melting pot of Greek and Egyptian scholarship. This rich intellectual environment provided a foundation for advancements in many fields, including mathematics.
Therefore, when considering the options presented by the student, B) Alexandria is the correct answer to the question of which place was the mathematical center of the world in the 4th century BC.