Write a multi-choice question for the following article, with the given choices and answer: Article: For anyone still doubting the belief that our emotions impact our physical health, a new study from New Zealand should be able to settle the matter. It reports that the physical wounds of healthy seniors healed more quickly if they wrote about their most upsetting experiences. This confirms the results of a 2010 study, and extends those findings to cover older adults-a group that is likely to suffer wounds (as from surgery), and one with less access to other ways of lowering tension (such as exercise). Reported in the journal Psychosomatic Medicine, a research team led by the University of Auckland's Elizabeth Broadbent made a study featuring 50 healthy adults ranging in age from 64 to 97. They were assigned to write for 20 minutes per day for three consecutive  days. Half were asked to write about the most upsetting experience in their life, describing their deepest thoughts, feelings, and emotions about the events, ideally not previously shared with others. The others were asked to write about their daily activities without mentioning emotions, opinions or beliefs. Two weeks after the third day of writing, all participants received a standard 4mm skin biopsy  on their inner arm. The very tiny wounds caused by the biopsy were photographed regularly over the following days to determine the rate at which they healed. On the 11th day after the biopsy, the wounds completely healed on 76.2 percent of those who had done the expressive writing. That was true of only 42.1 percent of those who had written about everyday activities. "The biological and psychological mechanisms   behind this effect remain unclear," the researchers wrote, noting that those who had done the expressive writing did not report lower stress levels or fewer depressive symptoms than the others in the control group. Even if they weren't consciously aware of feeling more relaxed or positive, the expressive writing appeared to have caused some sort of bodily reaction-probably involving their immune systems-that hastened their recovery. Options: A When they wrote. B Where they wrote. C What they wrote about. D How often they wrote. Answer: C What they wrote about. Question:
A:
What was the difference between the two groups of participants in the study?