3. Which of the following sentences is correctly punctuated?

On March 21 1985, our community held its bicentennial.

On March 21, 1985, our community held its bicentennial.

On March 21, 1985 our community held its bicentennial.

On March 21, 1985 our community, held its bicentennial.

The correct answer is: On March 21, 1985, our community held its bicentennial.