Q. Which of the following best explain why the lower course of a river is sometimes choked with sediments?1. The valley of a river is widest in its lower course.2. The velocity of a river in its lower course is low. 3. The delta sometimes develops in a river\'s lower course4. Much of the river water is drawn for irrigation in the lower course.Select the correct answer using the code given below:

1. 1, 2 and 3 only
2. 1, 3 and 4 only
3. 2 and 4 only
4. 1, 2 and 3 only