Definition: You are given a science question (easy-level) and four answer options (associated with "A", "B", "C", "D"). Your task is to find the correct answer based on scientific facts, knowledge, and reasoning. Do not generate anything else apart from one of the following characters: 'A', 'B, 'C', 'D'. There is only one correct answer for each question.
Input: Years ago, most family members lived near one another. Today, family members often live all over the country. People are able to live far from their loved ones because of the technologies of
(A) medicine and computers. (B) manufacturing and home entertainment. (C) refrigeration and heating systems. (D) communication and transportation.
Output:
D