MARCELLUS: "We do it wrong, being so majestical, To offer it the show of violence,
For it is as the air, invulnerable,
And our vain blows malicious mockery."

The word invulnerable comes from the Latin word vulnerare, meaning "to wound." Based on the meaning of the root word, this paragraph implies that Marcellus thinks that —

A. violence against others should be avoided.

B. violence against one's peers should be avoided.

C. violence against the Ghost would be punished.

D. violence against the Ghost would be useless.

D. violence against the Ghost would be useless.

If vulnerare means to wound, then invulnerable means something like not to wound. Marcellus says: "For it is as the air invulnerable."

That means the ghost is like air. You can't hurt air, you can't wound it. So if the ghost is like air, it also cannot be wounded. Trying to hurt the ghost would be useless, because it cannot be hurt. That's why the answer is d.

themselves

an intensive pronoun is a pronoun that ends in self or selves, such as himself, herself, themselves, yourself, ourselves. since band members is a third person plural, the correct intensive pronoun would be themselves. if the band was talked about as a collective noun, itself would be the appropriate intensive pronoun. intensive pronouns are used to add emphasis to the noun it's modifying which is why it directly follows it.