The 83(b) is not for the option per se, but the shares you own after you exercise the option.
> ... if the stock purchased pursuant to the exercise of an option is subject to a substantial risk of forfeiture, the service provider may make an IRC §83(b) election with respect to the stock received pursuant to the exercise of the option.
> ... if the stock purchased pursuant to the exercise of an option is subject to a substantial risk of forfeiture, the service provider may make an IRC §83(b) election with respect to the stock received pursuant to the exercise of the option.
https://www.irs.gov/businesses/corporations/equity-stock-bas...
Also see "Restricted Property" in Pub 525.
https://www.irs.gov/publications/p525#en_US_2020_publink1000...