#1 is incorrect because "were" is not the correct conjugation of "to be" in the past tense. "Were" should only be used by "you/you all," "he/she/they," and "we."
#2 is correct because "was" is the correct conjugation of "to be" in the past tense to fit with the "she" pronoun, the subject.
#3 is incorrect because it is the present tense.
#4 is incorrect because it's the conditional tense.
