Metallic materials are becoming more and more widely used. They have the common properties of
A. being very hard and having high melting points
B. having good electricity and heat conductivities
C. being white solids
D. reacting with acids easily to produce hydrogen gas​

Its B

Explanation:

hope its help by the way iam dream

the number of protons in the nucleus of a given element. has slight luster and conducts electricity at high temperatures like metal.but like a nonmetal,boron is brittle and does not conduct electricity well at low temperatures. in graphite, carbon is a soft,brittle solid.it is reflective,ductile,or malleable.

the answer to this question is 3.