Which of the following uses an introductory comma correctly?

1 Wishing she'd just called in sick, Suzy unlocked her filing cabinet and began her daily work.

2 Stop, there's not time for that!

3 Roberta needs to purchase eggs, milk, and bread.

The sentence that uses an introductory comma correctly is option 1) "Wishing she'd just called in sick, Suzy unlocked her filing cabinet and began her daily work." In this case, the comma is used after the subordinate clause to introduce the main sentence.

Option number 2 is not using an introductory comma, but the comma is separating two ideas.

And in option number 3, the comma is used to list a series of related items (eggs, milk, and bread).