Sentence Correction (SC) | Re: Neither Martha or her sisters are going on vacation.

For correlative conjunctions, the verb takes the number of nearest noun.
Further, the correct conjunction is Neither..Nor, not Neither..Or.

A.Neither Marthaor her sisters are going on vacation.

B.Neither Marthaor her sisters is going on vacation.

C. Neither any of her sisters norMartha are going on vacation.

D. Neither Martha nor hersisters are going on vacation.

E. Neither Martha nor hersisters is going on vacation.

D is the correct answer.
...

---