Definition: 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.
Input: original question: What is the unit of frequency in the measurement system used by [Siemens]?
answer: kilohertz, gigahertz, megahertz...
answer type: Unit of frequency.
auxiliary information: The siemens is the unit of electric conductance, electric susceptance and electric admittance in the International System of Units. Conductance, susceptance, and admittance are the reciprocals of resistance, reactance, and impedance respectively; hence one siemens is equal to the reciprocal of one ohm, and is also referred to as the mho. The 14th General Conference on Weights and Measures approved the addition of the siemens as a derived unit in 1971. The unit is named after Ernst Werner von Siemens. As with every SI unit whose name is derived from the proper name of a person, the first letter of its symbol is upper case; the lower-case "s" is the symbol for the second. When an SI unit is spelled out in English, it should always begin with a lower-case letter, except where any word would be capitalized. In English, the same form siemens is used both for the singular and plural.

[Siemens] uses what unit of frequency?