Figure 1 shows a pseudocode algorithm designed to calculate a discount based on a customer's age.
Figure 1
1 age ← USERINPUT
2 discount ← 0.0
3 IF age <= 18 THEN
4 discount ← 0.2
5 ELSE
6 discount ← 0.05
7 ENDIF
Which line number shows where selection is first used in the algorithm in Figure 1?
Line number 1
Line number 2
Line number 3
Line number 4