Which sentence correctly uses the subjunctive mood?

The subjunctive mood is used to express wishes, demands, suggestions, or hypothetical situations that are contrary to fact. It often employs the base form of the verb (e.g., 'be' instead of 'is/was') after certain verbs or phrases. In the sentence, "I demand that he be present" (C), the verb 'demand' triggers the subjunctive mood, requiring the base form 'be' rather than 'is' or 'was'. This correctly expresses a strong requirement. Let's examine why the others are incorrect: "I wish he was here" (A) should be "I wish he were here" for a hypothetical wish. "I suggest that he arrives early" (B) should be "I suggest that he arrive early" to express a suggestion. "If I was you, I would go" (D) should be "If I were you" for a hypothetical condition contrary to fact.