Answer:
See figure 1.
Explanation:
In this case have to take into account that all structures must have the formula: [tex]C_7H_16[/tex]. If we remember the general formula for alkanes: [tex]C_nH_2_n_+_2[/tex] if we have "7" carbons (n=7) we will have 16 hydrogens. Therefore all the structures that fit with this formula are alkanes.