Q: 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.
Which of the following describes a reason why companies irradiate some fruits and vegetables before they are sold to the public?
(A) to improve the flavors by increasing the sugar content (B) to speed up the ripening of produce picked too early (C) to partially cook the produce before canning or freezing (D) to extend the shelf life by killing existing microorganisms
A:
D