Superheroes are fictional characters with 1) ________ powers who use their powers to fight crime and protect the public. Some popular superheroes include Superman, Batman, Spider-Man and Wonder Woman. Superheroes often have backstories that 2) ________ how they have gained their powers, 3) ________ being born with special powers, being bitten by a radioactive spider or being exposed to cosmic radiation. They usually have a specific outfit or clothing that they wear to hide their identity and protect 4) ________ while fighting crime. Superheroes have been a staple of popular culture 5) ________ decades, appearing in comics, movies, television shows, and video games.

Select the most appropriate option to fill in blank no. 4.

The correct answer is themselves.

Explanation:
In the given paragraph, blank no. 4 is part of the sentence: "They usually have a specific outfit or clothing that they wear to hide their identity and protect 4) ________ while fighting crime."

Here, the subject performing the action is the third-person plural pronoun "They" (referring back to "Superheroes").

When the subject and the object of a verb refer to the exact same people or entities, we use a reflexive pronoun. The reflexive pronoun that corresponds to "They" is "themselves".

Let's evaluate the options:
- themselves: Correct reflexive pronoun for the third-person plural subject "They".
- ourselves: Reflexive pronoun for the first-person plural subject "We".
- herself: Reflexive pronoun for the third-person singular feminine subject "She".
- himself: Reflexive pronoun for the third-person singular masculine subject "He".

Therefore, themselves is the most appropriate option to fill in blank no. 4.