Hi Mr Bill,
Welcome to the forum.
There are a few diff definitions, none of which are your answer given. INN is typically a larger B&B - even a staffed B&B. An Inn would be more than a typical sized B&B of 3 to 5 rooms.
There are B&B's on this forum who:
1) Serve breakfast to the rooms ONLY
2) Have mutliple tables for breakfast
3) Have mutliple seatings or breakfast times
4) Serve delivery to the room, on the patio, at a table or on the porch
5) Breakfast can be a gourmet meal, deluxe continental, country fried, full hot breakfast, buffet, etc
Traditional definitions would be a B&B is an OWNER-OCCUPIED lodging establishment. Typically a B&B is in a residential neighborhood or rural - not commercial disctrict (altho that is the sometimes the case). But rule of thumb is the owners of the residence operate the business and interact with the guests - whether at one table or multiple..