Answer:
Let's analyze the sentences and apply the constituency test:
(b) The old man on the park bench has been feeding the pigeons for years.
i. Yes
ii. The old man on the park bench has been feeding the pigeons for years, and the young girl has been doing it too.
iii. Substitution with 'doing it too'
(c) The student answered the question correctly.
i. Yes
ii. The student answered the question correctly, and the teacher did (so) too.
iii. Substitution with 'did (so) too'
(d) The monster likes to hide in the closet.
i. Yes
ii. The monster likes to hide in the closet, and the ghost does (so) too.
iii. Substitution with 'does (so) too'
(e) Herbert watched cartoons every morning while eating breakfast.
i. No (This sentence is a complex sentence with two clauses but not a single constituent.)