The assembly line would be my first choice.
I think its C. they recognized Abu Bakr as the rightful caliph of islam.
Answer: The correct answer is the Silk Road, also known as the Silk Route,
Explanation: The Silk Road was a network of trade routes that connected China and the Far East with the Middle East and Europe. The Silk Road was first established when the Han Dynasty in China officially started trade with the West in 130 B.C. The Silk Road routes then stayed in use until 1453 A.D., when the Ottoman Empire boycotted trade with China and closed them.
