A solid substance was tested in the laboratory. The test results are listed below:?

-dissolves in water

I agree with Thinkstoomuch’s Answers in most part.
Solid Cu, C will not be soluble in water. However glucose and CuBr2 will be soluble in water. At STP solubility of glucose (C6H12O6) is about 90g/ml. That eliminates choice 1 and 3.
When a compound ionizes in soln it makes electrolyte. Glucose will not ionize but CuBr2 will ionize to Cu++ and 2Br-, choice 4 can be eliminated.
The third clue is just there to confirm your answer and CuBr2 being an ionic compound will indeed have a relatively high melting point. 498°C to be exact.
Clearly, Cupric Bromide should be your Answer.
I hope this helps.

dissolves in water: choices 1,3,4 dont make sense at all and since CuBr2 is an soluble solid it dissolves in H2O
electrolyte: is an substance that dissociates electrolytes when dissolved so #2 is the only one that makes sense
Melts at high temp.- Ionic bonds is the strongest bonds and it takes a really high temp to break it. again CuBr2

Because, CuBr2 is ioni and will dissolve in a liquid. It is a salt which means it is solid. Since it is an ionic compound, it has ionic bonds which results in high melting temperature.

Cu doesn’t dissolve in water. Neither doesC. And C6H12O6 isn’t an electrolyte.