Last weekend， I visited an old friend with five children under the age of three.I found that changing diapers at their house is like working on a（n）（）line.

Last weekend， I visited an old friend with five children under the age of three.I found that changing diapers at their house is like working on a（n）（）line.
A.astonished
B.assumed
C.assembly
D.assault
正确答案：assembly