thE inCrEAsE in thE numBErs oF mArriED womEn EmployED outsiDE thE homE in thE 20th CEntury wAs not DuE to ______.
A．thEir EConomiC nECEssity
B．morE womEn EmployErs
C．shortAgE oF singlE womEn workErs
D．high mArriAgE rAtEs