Which one of the following sentences is punctuated correctly?
a. della arrived on time, it was just two o'clock.
b. i found a large, smooth, rock on the beach yesterday.
c. she kept my surprise a secret, but she had a hard time doing it.
d. darleen chose tara, holly, and, marlene as her lab partners.

C: She kept my surprise a secret, but she had a hard time doing it.

Delegates: representatives who cast votes at a political party's national convention. binding: if a primary or caucus is “binding” that means the delegates won in that contest are legally bound to vote for a particular candidate at the parties national convention.a primary is a preliminary election used to determine a party's nominee for a specific office. the winner of the party's caucus, or primary, wins the party nomination for that state. then the delegates meet at their party's national party convention, which is a formal gathering of all party delegates from all states.