Please choose the correct ending to complete the given sentence: River tubing: They go down the river on the their tubes as they try hard to stay afloat on the turbulent waves. several tubers

Ending1: bend down as they kayak on the rough waters. Ending2: are taking their turns on their tubes as their raft gets stuck in the rough waters. Ending3: are seen going down the river in groups of four as they pass by trees and rocks. Ending4: don't make it to the bottom as they fall behind the boat.

Answer format: ending1/ending2/ending3/ending4