单选题 When the workers are organized in trade unions, their employers find it hard to lay them ______ .

【正确答案】 C

【答案解析】lay off意为“解雇”，符合本句的意思。lay out摊开，陈设，规划；lay up储存，使……卧床；lay down放下，放弃；均不符合本句的意思。