Final answer:
The Middle Colonies were known for their significant cultural diversity and religious freedom, with Pennsylvania serving as a haven for Quakers and exemplifying religious tolerance.
Step-by-step explanation:
The colonial region that fostered the greatest cultural diversity and religious freedom was b) Middle Colonies. This area, including New York, New Jersey, and Pennsylvania, was known for its high levels of ethnic and religious diversity, largely due to the patterns of settlement established during both Dutch rule and English control, along with rapid economic development in the region. Religious tolerance was a notable feature of the middle colonies, with Pennsylvania, founded by William Penn as a haven for Quakers, exemplifying this characteristic.