In a Research Study Examining the Effects of Nutrition on the Physical

In a research study examining the effects of nutrition on the physical growth of children in early childhood,a researcher randomly assigns a group of children and their parents to meet with a dietician to receive proper dietary instruction.The other group of children do not receive proper dietary guidance.After two years of study,the researcher compares the average growth of the two groups by reviewing their height and weight.The independent variable in this study is ________ and the dependent variable is ________.

A) dietary instruction; height and weight
B) level of activity; height and weight
C) parental input; length of the dietary instruction
D) height and weight; dietary instruction