The correct options are
A Food is not properly chewed
B Food is not mixed with saliva
When we eat food, out teeth break large chunks of food into smaller particles. At the same time, food also mixes with saliva which contains enzymes that partially digests food. Saliva also lubricates the movement of food into the food pipe. Eating fast means that the food spends very less time in the mouth for all of these actions to take place. This puts a lot more pressure on the other parts of the digestive tract and can lead to indigestion.