3.1 problem 1 (A)
3.2 problem 1 (B)
3.3 problem 2 (C)
3.4 problem 2 (D)
3.5 problem 3 (E)
3.6 problem 3 (F)
3.7 problem 4 (G)
3.8 problem 4 (H)
3.9 problem 5 (I)
3.10 problem 5 (J)
3.11 problem 6
3.12 problem 7
3.13 problem 8
3.14 problem 9
3.15 problem 10
3.16 problem 11
3.17 problem 12
3.18 problem 13
3.19 problem 14
3.20 problem 15
3.21 problem 16
3.22 problem 17