A toy train has three carriages in a line. A bar magnet runs along the length of each carriage, so each end of a carriage is a magnetic pole. The ends are A and B on the first carriage, C and D on the second and E and F on the third, so end B faces end C and end D faces end E. End A is a south pole. Ends B and C attract each other, but ends D and E repel each other.
Which two ends, other than A, are south poles?
ends B and D
ends C and E
ends B and E
ends C and F