What is a summary? A. the most important argument in a text B. a statement of one or more opinions about a text C. the details that support an important idea in a text D. a retelling of the main ideas of a text in your own words

Chen's research team randomly assigned some newborns and their mothers either to a breastfeeding promotion group (where breastfeeding was encouraged, but not required) or to a normal pediatric care group (where breastfeeding was neither encouraged nor discouraged). which research method did they use?