How is I/O access configured for logical domains with no physical I/O access?

A.
Configured with virtual I/O devices that communicate with the I/O domain, which is not
configured as a service domain

B.
Configured with virtual I/O devices that communicate with a service domain

C.
Configured with virtual I/O devices that communicate with the root domain

D.
Configured with virtual I/O devices that communicate with the control domain

Explanation:
http://docs.oracle.com/cd/E23120_01/html/821-2854/ldomsmanager.html(see virtual
input/output, second para, first sentence)