Question

Which sentence demonstrates an error in parallel structure?
A.
The United States government appreciates your father's military service to this country and his support for troops stationed overseas.
B.
Felicia loved visiting Washington D.C. and was impressed by the city's stunning architecture and by its historical significance.
C.
Dmitri Mendeleev is known for creating the periodic table of elements and for introducing the metric system to Russia.
D.
The Food and Drug Administration (FDA) is responsible for regulating drugs, cosmetics, and food items and to provide science-based health information to the public.

Answer 1

D. The sentence mixes a gerund ("regulating") with an infinitive ("to provide"); they should be parallel (e.g., "regulating ... and providing ..." or "to regulate ... and to provide ...").