Your answer would be "was" I just took a quiz with the same question, Hope This Helped!
Answer:
The correct subjunctive verb for the sentence is were.
Explanation:
The mood is the form a verb takes to show how it is to be regarded. The subjunctive mood is the verb form to talk about hypothetical situations or to express a wish, a demand, or a suggestion. In this case, the verb to wish attracts the use of the subjunctive mood. Moreover, as the sentence expresses a wish, was becomes were.
