Which sentence shows correct punctuation of an introductory structure?

When I ran across the tile I lost my balance and slipped.
If I had stayed late on Friday, I could have caught up on my work.
Well I delivered the memo to Mr. Jenkins last week.
Miriam ran the copies, and then moved the files to the break room.

6 answers

is it A?
No.

Please check your book to learn about introductory phrases and clauses.
is it d maybe i think either that or c i don't think it could be b
What on earth have you learned about introductory phrases and clauses?
This site will help you.

http://grammar.ccc.commnet.edu/grammar/commas_intro.htm
I think the Answer is B. Ms. Sue is that correct?