Compose a new way to ask the same question. The new question must be asking the exact same thing as the original question does. Without any other information, you should be able to tell that the original question and the new question are the same. Preserve bracketed phrases in your new question. You can change the rest of the question provided the above requirements are satisfied. The new question must have a natural, fluent formulation, as if it were composed by a native English speaker. You will be given three pieces of information to help you create better questions. Those are: "Answer": the answer to the question, e.g., "Honolulu". "Answer Type": the type of the answer, e.g., "Location". "Auxiliary Information" is a detailed description of some concepts mentioned in the question, if any.

original question: How many drug classes include [BCG vaccine]?
answer: 2
answer type: Drug class.
auxiliary information: A vaccine containing bacillus Calmette-Guerin (BCG), an attenuated strain of Mycobacterium bovis, with non-specific immunoadjuvant and immunotherapeutic activities. Although the mechanism of its anti-tumor activity is unclear, immunization with BCG vaccine likely activates a Th1 cytokine response that includes the induction of interferon. Vaccination with BCG vaccine may be immunoprotective against infection with Mycobacterium tuberculosis.
[BCG vaccine] contains how many drug classes?

original question: Which measurement system has the permittivity units of [Farad per metre]?
answer: international system of units
answer type: Measurement System.
In which measurement system is the permittivity measured in [Farad per metre]?

original question: What is the automotive class of automobile model which sister model is [Ford Mustang]?
answer: roadster, sedan, compact car...
answer type: Automotive Class.
auxiliary information: The Ford Mustang is an American automobile manufactured by Ford. It was originally based on the platform of the second generation North American Ford Falcon, a compact car. The original Ford Mustang I four-seater concept car had evolved into the 1963 Mustang II two-seater prototype, which Ford used to pretest how the public would take interest in the first production Mustang which was released as the 1964 1/2, with a slight variation on the frontend and a top that was 2.7 inches shorter than the 1963 Mustang II. Introduced early on April 17, 1964, and thus dubbed as a "1964¬Ω" model by Mustang fans, the 1965 Mustang was the automaker's most successful launch since the Model A. The Mustang has undergone several transformations to its current sixth generation. The Mustang created the "pony car" class of American automobiles‚Äîsports-car like coupes with long hoods and short rear decks‚Äîand gave rise to competitors such as the Chevrolet Camaro, Pontiac Firebird, AMC Javelin, Chrysler's revamped Plymouth Barracuda and the first generation Dodge Challenger.

Which class is the automotive class of automobile model whose sister model is the [Ford Mustang]?