Final answer:
B. DVI-D is the correct answer, as it supports digital-only connections and is designed for transmitting digital video signals.
Step-by-step explanation:
The question asks which of the following supports digital-only connections. Among the options provided, B. DVI-D is the correct answer. DVI-D stands for Digital Visual Interface-Digital and only supports digital signals. This is opposed to DVI-A, which stands for DVI-Analog and only supports analog signals, DVI-I, which integrates both digital and analog connections, and VGA, which is an analog video connection standard.