While she was at the store.

What is the best way to add the dependent clause above to sentence 2?
A.
She found a cookbook with recipes while she was at the store for different cupcakes.
B.
While she found a cookbook with recipes, for different cupcakes she was at the store.
C.
She was for different cupcakes while at the store she found a cookbook with recipes.
D.
While she was at the store, she found a cookbook with recipes for different cupcakes.