A:
CH3-CH2-CH-CH2-CH3
......................|
...................CH2
......................|
..................CH3
3-etilpentan
B:
CH3-CH-CH2-CH3
............|
........CH3
2-metilbutan
C:
CH3-CH - CH -CH3
.............|.......|
........CH3..CH3
2,3-dimetilbutan
D:
CH3-CH-CH3
............|
........CH3
2-metilpropan