How is the underlined gerund phrase used in the sentence?

they heard the poodle's barking from the yard.
('the poodle's barking from the yard' is underlined.)
a.
subject

b.
object of a preposition

c.
predicate nominative

d.
direct object

What reasons does the speaker provide to support his viewpoint or claim in what to the slave is the fourth of july i read to speech and but i just don't fully understand the question i just want to make sure i get it right so to explain that the question is asking me to do. and you!