Answer:
B. n-octyl alcohol and 1-octene
Explanation:
Thin-layer chromatography (TLC) is a chromatography technique used to separate non-volatile mixtures. The principle is that different compounds in the sample mixture travel at different rates due to the differences in interactions with stationary phase and due to the differences in solubility in the solvent. The principal chemical property for separation using this technique is molecular polarity
You can intuit than hexadecane and octadecane don't have big polarity differences, also chlorobenzene and bromobenzene haven't.
An alcohol as n-octyl alcohol has different polarity than an alkene as 1-octene.
Thus, using thin layer chromatography is most easy to separate:
B. n-octyl alcohol and 1-octene
I hope it helps!