In the given sentence, both verb and auxiliary verb should be used in the same tense. It rules out option (a) and (d). Generally, the pronoun ‘I’ is followed by the verb ‘was’ in the past indefinite tense but to express desires, wishes or intents, the phrase ‘I were’ is used. In the given sentence, there is a wish and hence, the correct verb will be ‘were’. It rules out option (b).