A, B, and D are elements while C and E are compounds. The three are elements backside basically they are yet to bond with any other element to form a compound.
Although the mercury is in glass, this doesn’t change the fact that it is an element. Being in glass does not affect the independence it enjoys as an element. This serves to mean that even elements can be useful in their elemental states and this does not affect their initial state. They still remain as elements even if they are in a particular confinement.
The other two I.e lye and sugar are compounds as they contain more than one element which are mixed together in appropriate volume
