2

(a)  

3

(a)  

4

(a)  

5

(a)  

6

(a)  

7

(a)  

8

(a)  

9

(a)  

10

(a)  

11

(a)  

12

(a)  

13

(a)  

14

(a)  

15

(a)  

16

(a)  

17

(a)  

18

(a)  

19

(a)  

20

(a)