1 b
2 c
3 c
4 b
5 a
6 a
7 a
8 d
9 a
10 a
11 d
12 c
13 b
14 b
15 b
16
17 a
18 d
19 c
20 a
21
22 b
23 b
24 a
25 a
26 d
27 4VHe=VCH4
28 c
29 d
30 b
31 a
32 c
33 b
34 a
35 a
36 b
37 c
38 a
39 a
40 a