Using a custom animation effect, how do you make text appear on a slide by letter

Question:Using a custom animation effect, how do you make text appear on a slide by letter

1.Apply the animation scheme fade in one by one.

2.Apply an entrance effect, and then set it to by letter in the effect option dialog box

3. Apply the fly in entrance to the text, and then set its speed to very slow

4.All of the above

Answer:2