||C2A central business district. These districts are designed to serve the central retail marketing function of the entire Ann Arbor trade area which extends at least halfway to surrounding cities of comparable size. A prime characteristic of these districts is a core of intense pedestrian activity. Most persons entering the district will come by automobile and typically will park once to carry out several errands. The economic welfare of merchandising activities in these districts depend on the intense development of comparison shopping. In these districts each establishment contributes to the whole shopping center by adding to the variety of goods available and to the comparison shopping opportunities. This essentially interdependence of activities is given precedence in the regulation and the future planning of the district over any desire to permit automobiles to come directly to each establishment. Provision is made in the C3 district for these uses that need to have the customer come directly to each establishment. Office building activities are compatible with the purpose of the district as long as adequate and convenient automobile parking can be provided for both the office and the retail merchandising activity. Residential development above the street level is also an important component of the district's pedestrian orientation. Permitted principal uses. (a) Any principal use permitted in the C-1 local business district without limitation to floor area or seating capacity. (b) Hotels and motels. (c) Any retail business whose principal activity is the sale of new merchandise in an enclosed building, excepting uses, such as the following, which tend to detract from or interfere with a high intensity of pedestrian shopping activity: automobile dealers, boat dealers, mobile home dealers, motorcycle dealers, filling stations. (d) Retail sales in which both a workshop and a retail outlet or showroom are required, such as plumbing, electrician [electrical], interior decorating, upholstering and similar establishments of no more objectionable character, subject to the provision that not more than 50% of the total usable floor area of the establishment shall be used for servicing, repairing, manufacturing or processing activities. (e) Enclosed theaters, radio and television studios, excluding transmission and receiving towers, assembly halls, concert halls or similar places of assembly or entertainment. (f) Governmental, newspaper publishing plants, charitable institutions, local and suburban transit and passenger transportation facilities. (g) Any permitted principal use of the "R" dwelling districts. (h) Business and personal services which are performed within an enclosed building, including duplicating, addressing, blueprinting, printing, photographic reproduction and film processing. (i) Retail sales of garden and horticultural supplies, which may have an automobile loading area as an accessory use. Permitted accessory uses. (a) Those allowed in the R3 district.