Step-by-step explanation:
Based on the provided passage, the best-supported inference is that the news had a highly positive impact on the camp. The passage describes how the effect of the news was "like magic," brightening faces and dispelling gloomy thoughts. The use of phrases such as "faces brightened," "gloomy forebodings fled," and "laughter and pleasantries enlivened the place" indicates a significant improvement in the mood and atmosphere of the camp. Therefore, the inference that the news had a highly positive and uplifting effect on the people in the camp is best supported by the passage.