CO is not an element because CO is a Compound. Elements contain One capital and one lowercase letter. While Compounds contain two or more capital letters.
D. The number increases and then decreases for noble gases
Sucrose is insoluble in dichloromethane because dichloromethane is not a polar solvent.
Sucrose is soluble in water because the molecules of sucrose has the ability to react with the molecules of water and thereby forming hydrogen bond which enhance the dispersion of sucrose in the water.
Sugar can not react in a similar way with dichloromethane because they do not possess chemical species that can react together to form bonds. Thus, sugar is a polar substance which can not dissolve in a non-polar solvent.