Which of the following would best describe the characteristics of covalent materials? select one:
a. a. a brittle, transparent solid with a very high melting point.
b. b. a shiny, malleable solid with a very high melting point.
c. c. a non-conducting material with low melting and boiling points, likely liquid or gas at room temperature.
d. d. a brittle, opaque solid with a very high melting point.
e. e. a non-conducting solid at room temperature that will conduct if melted or dissolved.