<prompt> Most recommended film among the following is:C filmE filmD filmU film  <response>: The types of film used most often in the United States are Ultra-speed group D and INSIGHT high end of the E speed range with manual processing and F with automatic processing conditions. INSIGHT film is preferred because it requires approximately half the exposure time and thus half the radiation dose of Ultra-speed film. Multiple studies have found that EF-speed film is preferred because it has the same useful density range, latitude, contrast, and image quality as D-speed films and can be used in routine intraoral radiographic examinations without sacrifice of diagnostic information.The current F speed film require about 75 less exposure of E speed film and only 40 of D speed film.White and Pharoahs Oral Radiology Principles and Interpretation 8th edition 