How long does it take to upgrade from C1 to B1?

[DeJoy]

You can upgrade to a B1 license after holding a C1 license for more than three years. To upgrade from a C1 to a B1 license, you must meet the following four requirements: Hold a C1 license for more than three years; No record of accumulating 12 penalty points in any of the last three consecutive scoring cycles; Meet the physical requirements: Age: Between 21 and 50 years old; Height: At least 150 cm; Vision: Naked or corrected vision must reach at least 5.0 on the logarithmic visual acuity chart; Hearing: Able to distinguish the direction of sound with each ear at a distance of 50 cm from a tuning fork; Upper limbs: Both thumbs must be intact, and each hand must have at least three other fingers intact, with normal limb and finger movement; Lower limbs: Both lower limbs must be intact with normal movement function, and the length difference should not exceed 5 cm. Additional notes for upgrading: The B1 upgrade application can only be processed at the vehicle management office in the driver's registered residence.