Barium in a suitable form is administered to patients before

Barium in a suitable form is administered to patients before an X-ray examination of the stomach, because

1. Barium allows X-rays to pass through the stomach on account of its transparency to X-rays
2. Barium is a good absorber of y-rays and this helps the stomach to appear clearly in contrast with the other regions in the picture
3. Barium is a good absorder of X-rays and this helps the stomach to appear clearly in contrast with the other regions in the picture
4. Barium salts are white in colour and this helps the stomach to appear clearly in contrast with other region in the pictures