禁忌使用洋地黄的是

A．心功能不全

B．阵发性室上性心动过速

C．心房颤动

D．肥厚型梗阻性心肌病

E．心房扑动

Virtualization is an approach to IT that pools and shares (71) so that utilization is optimized and supplies automatically meet demand. Traditional IT environments are often silos, where both technology and human (72) are aligned around an application or business function. With a virtualized (73) , people, processes, and technology are focused on meeting service levels, (74) is allocated dynamically, resources are optimized, and the entire infrastructure is simplified and flexible. We offer a broad spectrum of virtualization (75) that allows customers to choose the most appropriate path and optimization focus for their IT infrastructure resources.

（71）（）

A.advantages

B.resources

C.benefits

D.precedents