Final answer:
The correct answer is 'b. Because such pilgrimages were common in the Middle Ages, they often served to bring people from different backgrounds together.' as it appropriately uses 'because' to establish a cause-and-effect relationship.
Step-by-step explanation:
The best way to connect sentences 2 and 3 with a subordinating conjunction is by conveying the cause-and-effect relationship between the commonality of pilgrimages in the Middle Ages and their role in bringing people together. Therefore, the correct answer is: b. Because such pilgrimages were common in the Middle Ages, they often served to bring people from different backgrounds together.
This option correctly uses 'because' to show the reason why pilgrimages had a unifying effect on people of various backgrounds. Unlike the other options, 'because' establishes a logical connection that one event ('such pilgrimages were common') is the reason for the other ('they often served to bring people from different backgrounds together').
The best way to connect sentences 2 and 3 with a subordinating conjunction is option a. Although such pilgrimages were common in the Middle Ages, they often served to bring people from different backgrounds together.
Therefore, the correct answer is: b. Because such pilgrimages were common in the Middle Ages, they often served to bring people from different backgrounds together.