One hundred voters were asked their opinions about two candidates running for a political seat in the federal parliament. Their responses to three questions are summarized as follows: 20 responses favoured Candidate A on all questions, 30 responses favoured Candidate B on all questions, 40 responses favoured Candidate A on Question 1, but Candidate B on Questions 2 and 3, and the remaining 10 responses favoured Candidate B on Question 1, but Candidate A on Questions 2 and 3. Based on this information, what percentage of voters favoured Candidate B on Question 2?
a) 20%
b) 30%
c) 40%
d) 50%