A decision ..... until the next meeting.

The sentence requires a verb in the present perfect or future simple tense to indicate an action that has not yet occurred or will not occur by a certain future point. Considering the context 'until the next meeting', the most appropriate choice is the present perfect passive voice, indicating that the decision has not been made up to this point in time and may or may not be made before the next meeting. The future simple passive voice 'will not be made' implies a certainty that the decision will not be made, which is not necessarily conveyed by the original sentence structure. The conditional 'would not be made' is typically used in hypothetical or past conditional contexts, which do not fit here. Therefore, 'has not been made' is the grammatically correct and contextually fitting option.