Question

Which sentence demonstrates an error in parallel structure?
A.
If you want to get a full scholarship to college, you will be expected to maintain a high GPA and to participate in extracurricular activities.
B.
The photographs were not acceptable because the lighting was too bright and the people's faces were out of focus.
C.
Contestants in the science fair will be judged based on their knowledge of the scientific method and considering their oral and visual presentation skills.
D.
In his acceptance speech, the city's new mayor promised to find ways to attract bigger businesses and pledged to decrease the crime rate by fifteen percent.