Final answer:
The line "Men's natures wrangle with inferior things, though great ones are their object" is spoken by Iago in Shakespeare's play Othello. It illustrates the conflict between human nature's desires and actions.
Step-by-step explanation:
The character who utters the line "Men's natures wrangle with inferior things, though great ones are their object" in Shakespeare's play Othello is b) Iago. This statement reflects on the often contradictory nature of human desires and actions, which is a recurrent theme throughout the play. Iago, known for his cunning and manipulative personality, uses such observations to further his own schemes and manipulate other characters.