D is not the correct answer for this passage. The correct answer is E - "nature of the phenomena that physicists study."
At the beginning of the passage, the author claims that philosophers of science prefer to focus on physics and "at the heart of this preference is a mistrust of uncertainty." Further down in the passage, the author states that biologists have been trying to emulate physicists by constructing their science as a set of universal laws. This means that physics is constructed as a set of universal laws.
If something arises from a universal law, it is "true everywhere and for all times," meaning that there is no uncertainty. As philosophers of science mistrust uncertainty, it makes sense that they would prefer physics to biology. Therefore, the preference of many philosophers of science for the field of study depends primarily upon the nature of the phenomena that physicists study.