Geography Question! EASY 10 POINTS!?

Question

After traveling down the rier for over 500miles you reach the large city of St. Loius MO you continue down to Cairo IL. a few miles past this town you arrve at the place where another large river calld______river. What is the river?

Answer 1

Cairo is located where the Mississippi river and Ohio river meet.

Answer 2

mississipi river.i really dont know that area well so im just guessing a major river.

Answer 3

Ohio River

Answer 4

Mississippi River?