Hiw does rhe specific seevice trade of business $($sstb$)$ classify impact taxpayers qualified business income deduction qbid?

$1$ its never eligible business income from a m sstb

$2$ can only claim a partial deduction regardless of there amunt of their income

$3$ may not be eligible for full deduction if there taxable incme is at or beliw earabkixh threshold fir their filing status

$4$ may only claim the full deduction if their taxable income exceeds an establiches theeshold for their filing status