Tiffany has a keen interest in the original theories of william sheldon regarding the relationship between body type and juvenile delinquency. she has duplicated the study using sheldon's original methodology to see if her results are compatible to sheldon's. such a study illustrates the concept of

Replication.

Explanation:

Tiffany has duplicated the study using Sheldon's original methodology to see if her results are compatible to Sheldon's. Such a study illustrates the concept of replication. Replication is one key aspect of the scientific method. As Tiffany used the original methodology to see if she obtains the same results she is duplicating the original study. Her results will be relevant in the area because she is an independent researcher.

i would say b. research typically uses a variety of sources