Select the most appropriate option to fill in the blank.

Either he is mad, or he feigns _____.

madness

The most appropriate option to fill in the blank is madness.

The sentence "Either he is mad, or he feigns madness" is a disjunctive sentence, which means that it presents two mutually exclusive options. The speaker is saying that the person in question is either actually mad, or they are pretending to be mad. The word "feigns" means to pretend to have or feel something that you do not actually have or feel.

In this case, the speaker is saying that the person in question is either actually mad, or they are pretending to be mad in order to fool someone. The fact that the speaker is using the word "or" means that they believe that one of these two options is true, but they are not sure which one.

The other options are not appropriate because they do not make sense in the context of the sentence. The word "happiness" does not make sense because the speaker is saying that the person in question is either mad or pretending to be mad. The words "calmness" and "sadness" do not make sense because they are not mutually exclusive with madness. A person can be mad and calm, or mad and sad.