Under which empire did Islam spread through West Africa?

I believe the answer is Bornu Empire if you mean near the West Africa

Explanation:

In the middle of the 11th century, the Kanem Empire, whose influence extended into Sudan, converted to Islam. At the same time but more toward West Africa, the reigning ruler of the Bornu Empire embraced Islam. As these kingdoms adopted Islam, their subjects thereafter followed suit. I hoped I helped, please correct me if I'm wrong!

it was the first amendment

because he created electricity