Which property below is shared by both carbohydrates and lipids? a. both have the same number of oxygen atoms b. both are sources of cellular energy c. both are dissolvable in water d. both have the same proportion of carbon-hydrogen bonds

We are asked to determined which of the following choices above will be the correct shared property of a lipid and carbohydrate. To know the answer we must evaluate each of the choices.
a. Both have the same number of oxygen atoms 
- This is incorrect. Oxygen atoms of carbohydrate and lipids are different since 
lipid are usually unsaturated.
b. Both are sources of cellular energy.
- Carbohydrates is the main energy source of human body while lipids are the standby energy source when all the carbohydrates are consumed in the body.
c.Both are dissolvable in water.
-This is incorrect. Lipids are non-polar while water is polar. Like dissolves Like.
d. Both have the same proportion of carbon-hydrogen atoms
-This is incorrect since Lipids are usually double bonded atoms. thus it contain lesser amount of carbon compared to carbohydrate.

Therefore, the correct answer to this is letter B. Both are sources of cellular energy.