Answer: a) The least capable people have little to offer but sincerity.
Step-by-step explanation:
In his poem "The Second Coming", William Butler Yeats talks of a metaphorical Second Coming similar to the Biblical one, the return of Jesus. However, in his view, the Second Coming seems to be a tragic one, since history seems to be doomed to repeat itself. We may interpret it as the rise of Nazism is Europe, the Second Coming of Evil, since not long before there had been a World War.
In the lines "The best lack all conviction, while the worst Are full of passionate intensity", Yeats seemingly expresses how difficult it has become to distinguish the good from the bad. If good people have no conviction, how can they be good? If the bad have intensity, what can they offer other than that? Their intensity, sincerity, won't help or save anyone. Quite the opposite, it may end killing.