The correct answer is the following: option b. Based on the context clues given in the sentence, the most likely meaning of inauspicious is unfavorable. The definition of inauspicious is an event that gives signs that success is unlikely. In the sentence provided in the question, the narrator gives context clues that helps the reader to understand the correct meaning of the word inauspicious. The narrators explains how the clouds that are gathering in the horizon were an inauspicious sign for an outdoor class, so Dara, who we assumed is the teacher or professor, decides to give the class indoor. The fact that the inauspicious sign made the teacher changed her mind gives the context clue of what the term means.