Two point sources are regarded as just resolved when the principal diffraction maximum of one image coincides with the first minimum of the other. If one considers diffraction through a circular aperture, this translates into the expression θ=1.22
λ
d
=1.22×
5000×10−8
10
=1.22×5×10−6=6×10−6rad Hence, the closest option is 10−6 rad