Question

How is the underlined pronoun in the sentence used? My plants are starting to grow; I have watered them daily. A. direct object B. object of a preposition C. possessive D. indirect object

Answer 1

C. Possessive 
This is because it's claiming that something is theirs.

Answer 2

It depends on which pronoun is underlined: 'my' or 'I' or 'them'.
If 'my' is underlined, then the correct answer is C) possessive.
If 'I' is underlined, then the correct answer is 'subject'.
And if 'them' is underlined, the correct answer is A) direct object.