Final answer:
The correct types of passive adapters for DVI-to-VGA connectivity are DVI-A to VGA and DVI-I to VGA, since they support analog signals.
Step-by-step explanation:
The types of passive adapters that enable DVI-to-VGA connectivity include DVI-A to VGA and DVI-I to VGA. Option A, DVI-D to VGA, does not support analog signals and therefore cannot be used with a VGA connector, which is entirely analog. Option D, DVI-A/D to VGA, is not a recognized standard connector type. DVI-I combines both digital and analog signals, which allows it to be converted to VGA with a simple pass-through adapter since VGA accepts analog signals. Likewise, DVI-A carries only analog signals, which makes it compatible with VGA.