mainframe customer would like to receive a proposal for a mainframe storage system with 120 TB raw capacity. The mainframe server load is not too high， and they need hard disk drives with the lowest possible power consumption to keep operating costs low. The customer will not increase the capacity of their mainframe applications in the future but rather invest later into their System p servers. Which of the following solutions best meets these requirements at the lowest cost（）
A、offer a DS8700 system with 600 GB FC drives
B、offer a DS8800 system with standard cabling and 600 GB SAS drives
C、offer a DS8800 system with business class cabling and 600 GB SAS drives
D、offer a DS8800 system with SATA drives
Given: When line 14 is reached， how many objects are eligible for the garbage collector？（）
A、 0
B、 1
C、 2
D、 3
E、 4
常用的采购方式中，有限竞争性竞标具有这样的优点：（）、（）、（）。
Given： Which three changes should be made to adapt this class to be used safely by multiple threads？（）
Adeclare reset（） using the synchronized keyword
Bdeclare getName（） using the synchronized keyword
Cdeclare getCount（） using the synchronized keyword
Ddeclare the constructor using the synchronized keyword
Edeclare increment（） using the synchronized keyword
BGAN使用电池开机时，不能开机，或不能保持开机状态的主要原因是什么？
有三个关系R、S和T如下：其中关系T由关系R和S通过某种操作得到，该操作为（ ）。
A、选择
B、投影
C、交
D、并