In Children Between the Ages of 4 and 15, the Results

In children between the ages of 4 and 15, the results from the nine working memory tests administered by Gathercole et al. (2004) ________.

A) show a linear increase in performance from age four through adolescence
B) show a non-linear increase in performance, first steep and then almost flat, from age four through adolescence
C) show a non-linear increase in performance, first almost flat and then steep, from age four through adolescence
D) indicate that working memory cannot be measured reliably before the age of 7