HELP!HELP!HELP! CD11--Q28

At an orientation meeting, the travelers were told that a visa, a landing card, and evidence of inoculation against typhoid fever would be needed by each of them.

1. a visa, a landing card, and evidence of inoculation against typhoid fever would be needed by each of them

2. they would need a visa, a landing visa, and evidence of their being inoculated against typhoid fever

3. they would need evidence of being inoculated against typhoid fever and a visa and landing card

4. they would each need a visa, a landing card, and evidence of inoculation against typhoid fever

5. they would need visas, landing cards, and evidence of inoculation against typhoid fever for each of them.

为什麽选D不选A，区别的关键点究竟是什麽？ 请高人赐教！！！