I too believe the answer to be the third option: misery.
Explanation:
The poem presents a mournful tone for, even though the ship has safely returned home, the captain has died. The speaker cannot fully celebrate the long-awaited victory. He walks sadly, treads mournfully, around the captain's body.
Walt Whitman wrote this poem shortly after Abraham Lincoln died. Its metaphor presents Lincoln as the dead captain, the ship being the nation, still united after a gruesome civil war.
I read the poem and I am completely positive that the connotation used in words”mournful tread” is <em>misery </em><u>not celebration or fury or romance </u>
