The destruction of their natural habitat has compelled snow leopards to seek refuge outside their usual summer range in northern India. Fortunately, the snow leopards frequently are able to find shelters that are similar to ones in their original summer habitat: isolated caves on rocky slopes that are protected from harsh winds. What is the impact of the author’s use of the word fortunately on the tone of the paragraph? A It provides an ironic tone to a serious topic. B It provides a light-hearted tone to a serious topic. C It provides a negative tone to a serious topic. D It provides a positive tone to a serious topic.