21

(a)  

22

(a)  

23

(a)  

24

(a)  

25

(a)  

26

(a)  

27

(a)  

28

(a)  

29

(a)  

30

(a)  

40

(a)  

50

(a)  

60

(a)  

70

(a)  

80

(a)  

90

(a)  

100

(a)