To add body to a hearty broth, you may use

A. Water

B. Onions

C. Cheese

D. Pasta

B. Onions

Explanation:

In order to add body to a hearthy broad you just need to add onions, from the options, body is known as the flavor or roundness of the mix in the soup, the flavor of the onion and the mixing of that flavor in the broath will make the hearthy broath to bring together all of the flavors of the meat and fats that are already contained in the broath and will increase and make the flavors in the broath more round.