The foremost reason which contributed to the decline of the Han dynasty was:
D) Internal Peasant Revolts, also known as Yellow Turban Rebellion or Yellow Scarves Rebellion.
E) Attacks by powerful warlords among whom Dong Zhou was the one who making a Han child a dummy king took control of the power in the background.
C) Destruction caused by natural disasters.
All of these were the major factors in the last days of Han Dynasty.