Correct

祸根

/ huògēn /
Strokes

Definition

root of the trouble/cause of the ruin

Example

As a Noun

root of trouble; cause of ruin; bane; curse; apple of discord

1
de
cái
财富
chéng
le
de
huògēn
祸根
  

His wealth proved a curse to him.

2
Huògēn
祸根
chú
  
,
hòuhuànqíong
后患无穷
  

There would be endless trouble unless the source of disaster is uprooted/eradicated.

3
Mái
xià
huògēn
祸根

lay up trouble for the future