Which of the Following Is the Best Example of a Cross-Sectional

Multiple Choice

Which of the following is the best example of a cross-sectional research study?

A) Dr.Huang assessed the eye-hand coordination of the second,fourth,and sixth graders of Maple Leaf Elementary School in September 2006.
B) Dr.Sanchez assessed the eye-hand coordination of the second,fourth,and sixth graders of Maple Leaf Elementary School in December 2006,and the same children will be tested again in 2008,2010,and 2012.
C) Each year at the beginning of the school year,the five children of the Jones family visit their family doctor to have physical exams.
D) Each year the five-year-olds of Washington,D.C. ,are given number and letter proficiency exams before they begin kindergarten.