Son los principios éticos que deben orientar nuestras decisiones. ​
a) justicia, equidad y respeto
b)solidaridad, prudencia y paciencia
c)obediencia, respeto y fortaleza
d) igualdad, honradez y justicia

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?