As time goes on, the only solution that will be common in medium to large implementations is the use of Layer 3 switches. The other two solutions had their time, but as the technology and industry have evolved, the third solution has grown to be an easier (and overall cheaper) solution than its predecessors.
The use of VLANs on modern networks has continued to evolve and grow. A good knowledge of their purpose and how they are typically configured into an overall networking architecture is very important. I hope that this article gives you a better idea of how VLANs can be configured to communicate with one another, increasing your knowledge of how virtual networks will continue to be implemented in future networks.