The answer is: [C]: "Niether Mike nor Marvin believed in Superman." _____________________________________________________________ The misspelled word is: "<em>Niether</em>" {sic} — which should be changed to the correct spelling — "<u><em>Neither</em></u>". _______________________________________________________________
Although the sentence with the misspelled word is c, because neither is misspelled, there is some capitalization era's in each sentence which could lead to misspelling as well.
An independent clause can stand on its own as a sentence such as Dave sleeps and a dependent clause can't stand alone as a sentence like when dave sleeps