The company is implementing XenDesktop globally for desktop virtualization.
How should the architect recommend installment of controllers for high availability?

A.
Install three controllers in each datacenter.

B.
Install three controllers in New York, three in London, and three in Singapore.

C.
Install three controllers in Hong Kong, three in New York, and three in Berlin.

D.
Install four controllers in New York, four in Sydney, and one in London.