Final answer:
To switch an entire building to a gigabit network, upgrade network cables, install gigabit switches, and test network connectivity. All these steps are necessary for a successful transition.
Step-by-step explanation:
If an entire building is switching over to a gigabit network, handling this project would require a comprehensive approach that includes several key steps. First and foremost, it is necessary to upgrade network cables to Cat 5e or Cat 6 if they are not already in place, as these are capable of supporting gigabit speeds. After cable upgrades, you would need to install gigabit switches, replacing any old hardware that cannot support gigabit speeds. Lastly, it is crucial to test network connectivity to ensure that all connections are operating at the desired speeds and that there are no issues that could impede performance. Therefore, the correct way to handle the project would be D) All of the above.