100. The applicability of business and resident rates is governed by the actual and obvious use made of the service. The use which is to be made of the service shall be ascertained from the applicant at the time of application for service. 1. BUSINESS RATES APPLY AT THE FOLLOWING LOCATIONS: a. In offices, stores, factories and all other places of a strictly business nature b. In boarding houses and rooming houses with more than five rooms available for rent (except as noted under Subparagraph (e) below), colleges, clubs, lodges, schools, (except private or parochial school now served under a residential rate) libraries, churches (except in the pastor's study), lobbies and halls of hotels, apartment buildings, hospitals and private and public institutions c. At any location when the listing of "office" is provided or when any title indicating a trade, occupation or profession is listed (except as modified under the directory listing schedule) and at any location classified under Paragraph (2) below regardless of the form of listing when extension of service is provided to a place not a part of a domestic establishment d. At a residence location when the subscriber has no regular business telephone service and the use of the service by himself, members of his household or his guests is more of a business than residential nature as might be indicated by advertising through newspapers, hand-bills, billboards, circulars, business cards or otherwise e. In general, in any place where the substantial use of the service is occupational rather than domestic2. RESIDENCE RATES APPLY AT THE FOLLOWING LOCATIONS: a. In private residence or residential apartment or hotels and apartment houses when business listings are not provided and when all stations are in locations which are a part of a domestic establishment b. In the homes of nurses (but not nurses' dormitories)3. CHANGE FROM RESIDENCE TO BUSINESS SERVICE If it is found that a subscriber is using residential service for business purposes, the company shall thereafter require the subscriber to take a business service except in cases where the subscriber thereafter uses the service for residence and domestic purposes only.