The sentence that uses parallelism correctly is:

a. After the apartment building's fire alarm went off, the street was filled with sleepy children, restless parents, and their scared pets.
b. After the apartment building's fire alarm went off, the street was filled with sleepy children, restless parents, and pets that were afraid.
c. After the apartment building's fire alarm went off, the street was filled with sleepy children, restless parents, and frightened pets.