The most accurate response to compare the growth of Islam and Christianity in the Middle East between 300 and 1500 CE would be:
During this time, Islam became the dominant religion in the region. Christianity was less established in the Middle East during this time, but its influence was still felt during the Crusades.
This is because Islam emerged in the 7th century CE and quickly spread throughout the Middle East and beyond, becoming the dominant religion in the region. Christianity, while having earlier roots in the area, faced various challenges and changes during this period but remained influential, especially during events like the Crusades.