A is the answer.
“Those he commands move only in command, Nothing in love” = the people only follow his commands because they have to as he is their king, not because they love or respect him.
“Now does he feel his title Hang loose about him, like a giant’s robe Upon a dwarfish thief.”
= Because the people don’t love/respect him he feels like he is unfit/undeserving of his title/crown, and this is compared to a dwarf wearing a ill-fitting stolen robe of a giant as Macbeth pretty much “stole” the crown.