(a) Visibility 8km : Clear of clouds
(b) Visibility 5km : distance from clouds: 1500m horizontal, 1000 ft; vertical
(c) Visibility 8km : distance from clouds: 1500m horizontal, 1000 ft; vertical
(d) No minima defined: VFR not permitted

 

The examiners logic is that 8km vis, 1,500m horiz & 1,000ft vert will be satisfactory for all classes of airspace. This is the feedback just as we received it and if this question appeared in a UK exam we would appeal it because, as you pointed out, answer (a) is correct for class B airspace and answer (d) is correct for class A airspace.