"bien que" is a conjunction that introduces a subordinate clause expressing a contrast or concession. It is followed by the subjunctive mood in French. The subjunctive is used to express subjective actions, desires, doubts, or hypothetical situations. In this case, "bien que" indicates a contrast or concession, suggesting that the action or situation described in the subordinate clause may not be certain or real. Therefore, the correct answer is "Subjonctif."