In economics, a final good is a commodity that is used by the consumer to satisfy current wants or needs, as opposed to an intermediate good, which is used to produce other goods.
Let's analyze the options:
(B) Wheat sold to a floor mill: This is an intermediate good because the mill will process the wheat into flour, which will be used to produce other goods like bread or biscuits.
(C) Shirt buttons sold to a tailor: These are intermediate goods because the tailor will use them as inputs to produce a final good, which is the shirt.
(D) Paper sold to a book binder: This is an intermediate good because the book binder will use it as an input to produce a final good, which is a book.
(A) Idli made by a cook in a family: This idli is prepared for direct consumption by the family. It is not being used as an input for further commercial production. It represents the end of the production chain for that item. Therefore, it is considered a final good in this context.