The aperture diameter of telescope is 5m. The separation between the moon and the earth is 4×105 km. With light of wavelength of 5500A˚, the minimum separation between objects on the surface of moon, so that they are just resolved, is close to: [Main 9 Jan. 2020 I]
(a) 60m
(b) 20m
(c) 200m
(d) 600m