Concept:Islam entered Nigeria through trans-Saharan trade routes, first reaching the northern region around the 11th century.
Explanation:Islamic influence reached Nigeria from North Africa across the Sahara desert.
The earliest recorded appearance of Islam in Nigeria was in Borno, located in the northeast.
This happened during the eleventh century.
From Borno, Islam later spread to Hausaland in the northwest.
Its presence became especially noticeable in major cities such as Kano and Katsina.
Therefore, the beginning of Islam in Nigeria is historically traced to the 11th century, not the 12th, 17th, or 18th century.
Answer:The correct option is A: 11th century.