Explanation:

The correct option is (a) Virtual Reality. In the context of computer technology, VR is the widely recognized acronym for Virtual Reality. Virtual Reality refers to a simulated experience that can be similar to or completely different from the real world, typically achieved through specialized headsets that provide immersive visual and auditory feedback to the user. Options (b) Visual Reality, (c) Vocal Resonance, and (d) Visual Range are not standard or recognized expansions for VR in computer technology. 'Visual Reality' is not a defined term. 'Vocal Resonance' relates to sound and speech, and 'Visual Range' pertains to optics or visibility, neither of which aligns with the common usage of VR in computing.