The passage also gives us a great account of the family of Alexander Fleming. We learn that two of his brothers, John and Robert were joined by him as he went to stay with his elder brother, Thomas. It is Thomas only who was on his way to become a successful oculist in his professional life. Oculist is another word for an eye doctor or specialist, therefore the correct answer is option C.

The passage informs us about the formative years of Alexander Fleming’s life and how the events in those times took a turn to the benefit of his life and that of the humanity in turn. We also learn about the fact that he was greatly inspired by nature during his daily hikes up and down the hills as he went to school. The answer that best corresponds to this criterion is given to us in option D, which is the correct answer. All the rest of the options are either inappropriate to be used here, or are wrong to be used, so are incorrect answers.

The sentence in the passage has been used to explain the change in the financial conditions of Alexander’s family. This change in the financial conditions lead to the creation of far more possibilities for his future, due to which, he could make all the advancements in the field of science; which lead to the benefit of the human race as well. The correct answer, from among the options provided to us, in this case is option B as it explains the details in the passage properly. The rest options are incorrect answers as they supply us with wrong or incomplete details.