There are different types of data that you may want to display depending on the information that people need. These data types are the following: individual, pedigree, sample, and marker. The database fields are usually recorded depending on the level that they are at.
There are also different types of data that will be placed in each field. Letter B is the right code to use so that you can get the effect that you want. The relationship that will be evident will depend on the auto-populated defaults but this can be changed accordingly depending on your requirements.