Correct

侧线

/ cè xiàn / 
Strokes

Example

As a Noun

lateral line (of fish)

1
Cèxiàn
侧线
qìguān
器官

lateral-line organ

2
Cèxiàn
侧线
lín
鳞

lateral-line scale

As a Noun

siding; side track/line