A Study That Assessed Arithmetic Calculations by Unschooled 9- and 15-Year-Old

A study that assessed arithmetic calculations by unschooled 9- and 15-year-old Brazilian street vendors found that the children answered questions presented the way that they typically are in school correctly

A) 18% of the time.
B) 37% of the time.
C) 64% of the time.
D) 98% of the time.