Where is the license plate number Gan O from?

[SanBrandon]

Gan O refers to the special license plates used by vehicles of the public security, procuratorial, and judicial authorities in Gansu Province. The license plate numbers for various prefecture-level cities in Gansu Province are as follows: Gan A represents Lanzhou City, Gan B represents Jiayuguan, Gan C represents Jinchang, Gan D represents Baiyin, Gan E represents Tianshui, Gan F represents Jiuquan, Gan G represents Zhangye, Gan H represents Wuwei, Gan J represents Dingxi, Gan K represents Longnan, Gan L represents Pingliang, Gan M represents Qingyang, Gan N represents Linxia Hui Autonomous Prefecture, and Gan P represents Gannan Tibetan Autonomous Prefecture. 'Gan' refers to Gansu Province, and the letter following the Chinese character represents the code of the vehicle management office in the prefecture-level city. The letter 'O' is usually used for license plates of specific vehicles belonging to authoritative departments such as public security, procuratorial, and judicial authorities. Private vehicles cannot use 'O' as their license plate number.