Ann made a 3 -step staircase using 18 toothpicks as shown in the figure. How many toothpicks does she need to add to complete a 5-step staircase?

**Answer Choices**

A. 9

B. 18

C. 20

D. 22

E. 24

Ann made a 3 -step staircase using 18 toothpicks as shown in the figure. How many toothpicks does she need to add to complete a 5-step staircase?

**Answer Choices**

A. 9

B. 18

C. 20

D. 22

E. 24