Write the structures of all possible dihalogen derivatives of propane.

(N/A) There are four possible dihalogen derivatives of propane. The structures are as follows:
$(i)$ $CH_3-CH_2-CHBr_2$ $(1,1-Dibromopropane)$
$(ii)$ $CH_3-CBr_2-CH_3$ $(2,2-Dibromopropane)$
$(iii)$ $CH_2Br-CHBr-CH_3$ $(1,2-Dibromopropane)$
$(iv)$ $CH_2Br-CH_2-CH_2Br$ $(1,3-Dibromopropane)$