The best and most correct answer among the choices provided by the question is the second choice.
Carbon can easily bond with other atoms because it is an organic element.
I hope my answer has come to your help. God bless and have a nice day ahead!
Explanation:
impurities affect both melting point and boiling point
in the case of melting point it lowers the melting point
so I guess one of the samples Ie contained impurities
