ok so the equation for arc length is:
s=r θ
where s=arc length, r=radius and θ=angle
so before we can just substitute stuff in we gotta change the angle into radians. in order to do that we take the angle measure 90 degrees and multiply that by (π/180) which is π/2. you can do the math for this or use a unit circle:)
now let’s fill stuff in
s= (6) (π/2)
multiply
s=6π/2
simplify
s=3π
add a label and your arc length is 3π yd. so the correct answer is A