Correct

开线

/ kāixiàn / 
Strokes

Definition

to come unsewn/to split at the seam

Example

As a Verb

burst at the seams; become unsewn

1
Kùtuǐ
裤腿
kāi
开
xiàn
线
le
了
  
。

A seam in the trouser leg came apart/unsewn.