Final answer:
Marty fed Shiloh biscuits first, marking the beginning of their friendship in the novel "Shiloh" by Phyllis Reynolds Naylor.
Step-by-step explanation:
The first thing Marty fed to Shiloh was B) Biscuits. In the novel "Shiloh" by Phyllis Reynolds Naylor, Marty Preston is a young boy who finds a beagle in the hills behind his house.
Though he doesn't have much to offer, he gives Shiloh some biscuits, which is the first step in developing their strong friendship. This event is an important part of the story, as it showcases Marty's kindness and the beginning of his bond with Shiloh.