tolong di jawab ya..

OB = 1, AO = 1,
AB = sqrt (1^2 + 1^2) = sqrt (1+1) =
akar 2
AB = diameter
Luas Arsir = 1/4 × (TI) × d x d
= 1/4 x (TI) x (akar 2) x (akar 2)
= 1/4 x 2 x (TI) = 2/4 (TI) = (TI) / 2

jawabannya = B