A Researcher Administers a 40-Item Instrument That Measures Anxiety to 30

A researcher administers a 40-item instrument that measures anxiety to 30 mothers of 9-month-old triplets, repeating it in 2 weeks. Over half of the scores are higher. Why?

A) The mothers are more anxious. The babies are becoming more mobile, and the mothers' anxiety is well founded.
B) There may have been random error of measurement. The researcher should compare the group means; if they are the same, it's only random error.
C) This may represent systematic error of measurement.
D) This may have poor validity for this population and concept.
E) This test may have poor reliability for this population and concept.