How long does it take for a C1 license to upgrade to a B1?

[Sauron]

C1 can be upgraded to B1 after three years. To upgrade from a C1 driver's license to a B1, the following four requirements must be met: Hold a C1 driver's license for more than three years; No record of accumulating 12 penalty points in the most recent three consecutive scoring cycles; Meet the physical requirements: Age: Between 21 and 50 years old; Height: At least 150 cm; Vision: Naked or corrected visual acuity of 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 intact, with at least three fingers intact on each hand, and normal limb and finger movement function; Lower limbs: Both lower limbs intact with normal movement function, and the difference in length not exceeding 5 cm. Note: The B1 upgrade application can only be processed at the vehicle management office in the driver's registered residence.