The second sentence (B.) should come last in a paragraph.
A paradox is in contrary to expectations. It may also refer to perceived opinion or existing belief. It is a statement which includes ultimate truth but is self-contradictory. To make the reader think in an innovative way, a paradox is used.
Few examples of paradox are:
“I can resist anything but temptation.” – Oscar Wilde
Therefore, best definition of paradox is the pairing of opposites.
The tone in the last stanza is regretful. The poem is about a man who received advice from a wise man that he can give away all his wealth but not his heart. He's told that once you give away your heart, you lose it and end up regretting it. He experiences it and regrets afterwards.