Maria Is Studying the Effects of Calcium on the Development

Multiple Choice

Maria is studying the effects of calcium on the development of children.So she administers varying levels of calcium to two groups of children,one group consisting of children aged five and the other group consisting of children aged ten.She studies the growth rate of these two groups regularly over a period of one year.On the basis of the given evidence,it would be most accurate to say that Maria is using _____ research design.

A) only the cross-sectional
B) the sequential
C) only the longitudinal
D) the single case experimental