Answer:
The answer to your question is letters B, C and, D.
Explanation:
A. the sample melts at 1768 K The melting point of copper is 1357.77°K, not 1768°K so this is not the right answer.
B. atoms in the sample react with oxygen Copper reacts slowly with oxygen and form a layer of brown-black copper oxide. This option is correct.
C. each atom in the sample has 29 protons Copper has 29 protons, so this option is correct.
D. the sample can conduct electricity Copper is a good conductor of heat and electricity. This option is correct.