A、Consult the waiter about the dish in question. B、Tell everyone that you have certain dietary restrictions. C、Write beforehand

American businessmen frequently use social situations to make business deals. One of the best examples of this practice is the business lunch. Therefore, knowing how to conduct yourself at a business lunch is often just as important as the business discussion.
    For formal business lunches, it is wise to phone at least 1 day ahead to reserve a table. After you have been seated and given a menu, your waiter will come and ask if you would like to order anything to drink. Nowadays, it is quite acceptable to order a mineral water, a soda, or fruit juice, apart from wine or a mixed drink. After he has taken your beverage order, your waiter will leave you to make your food selection from the menu you have been given. It is the host’s responsibility to discover whether or not his guests have any special dietary restrictions. If, however, a host does not do that, a guest should not announce his dietary practices to everyone at the table. Instead, he should discreetly ask the waiter about the ingredients of any dish in question. He should also have in mind a second dish that he might order, just in case. Usually, the host will allow his guests to order first. Occasionally, a host may collect orders ahead of time and place them himself.
    Napkins should be placed on your lap, and used periodically to wipe the corners of your mouth, especially when you are eating soup, salad with dressing, or an entrée in a sauce. When you finish the meal, the napkin is then placed on the table beside the plate.