Read this excerpt from the last duchess what is the main complaint of the speaker against the lady referred to in the poem?

The correct answer to the question stated above is:

C. The lady did not value the Duke enough and treated him like she treated everyone else.

The speaker described her as someone who gets easily impressed by human and nature that she forgot to give importance to the Duke's hierarchy in the society. In addition, he was insulted by the lady's undervaluing his family name.