QusIf an element have margin values 20px for top, 20px for bottom, 30px for right, 30px for left. Then which of the following is the correct way to set the margin?
A. margin: 20px 20px 30px 30px
B. margin: 30px 20px
C. margin: 20px 30px
D. margin: 30px 30px 20px 20px