The passage states that “30% of doctor in Great Britain work, AT LEAST some of the time for the commercial sector”. The ‘at least’ suggests that the 30% of doctors mentioned consists of those who work in both sectors and in commercial sector only. Therefore the remaining 70% of doctors work in public health service only.
1- This is true as 70% of doctors work in public service only
2- This is correct as 70% work in public sector only whilst the remaining 30% work either in commercial service only or both sector.
3- This cannot be verified from the information given.
Since statements 1 and 2 are correct, C is the answer.