Oh okay, so do you have any more info?
OK so when I did this the answer was a and I got it right
Niger and Congo are two rivers after which countries are named (actually in both cases two countries each) - and those are African countries, so they must be in Africa.
Zambezi is a river in Angola and Namibia.
Tigris is a River in Mesopotamia, in Asia - so that's the correct answer!
D tornados. tornados have to do with warm and cold fronts of air coming in contact with each other.