The topic of western economics! For a detailed explanation, please!

ed=-dQ/dP×P/Q

abc:

-:D dQ/dP & gt； C & gtB

p/Q:B& gt； C & gtD

The first one is incomparable.

aeH:

-:D dQ/dP & gt； C & gtB

p/Q :D & gt； C & gtB

So H>e>a