Final answer:
The correct answer is C. The phrase "a doctor practicing in Nagasaki" uses metonymy, a literary device where something is referred to by a closely associated name, in this case, 'Nagasaki' which is associated with the atomic bombing.
Step-by-step explanation:
The literary device used in the phrase "a doctor practicing in Nagasaki" is metonymy. Metonymy is a figure of speech where a thing or concept is referred to by the name of something closely associated with that thing or concept. In the phrase given, the word 'Nagasaki' is used not just to specify the location where Dr. Tatsuichiro Akizuki practiced medicine, but it also evokes the association with the atomic bombing during World War II, hinting at the context within which he worked without directly mentioning the war or the bombing.
Metonymy is a figure of speech in which one word or phrase is substituted for another with which it is closely associated. In this case, the word 'Nagasaki' is used to represent the specific place where Dr. Tatsuichiro Akizuki practices as a doctor.