What profession did Marco Polo have before he became a government official at the court of Kublai Khan?

The correct answer is B. Venetian trader.

Before Marco Polo became a government official at the court of Kublai Khan, he was primarily known as a trader from Venice. His travels along the Silk Road and beyond, trading goods, exposed him to various cultures and ultimately led him to serve in the court of the Mongolian emperor. If you need more details or further assistance, feel free to ask!