Infrastructure as a Service (IaaS)

Correct Answer: Data Transfer Optimization

The best strategy to optimize network costs after moving to Infrastructure as a Service (IaaS) is Data Transfer Optimization. This method focuses on reducing the amount of data that needs to be transferred over the network, which directly affects the network cost. The other answers do not directly address the issue of network costs. Increasing Server Resources, would possibly increase costs rather than reduce them. Migrating to another IaaS provider might not necessarily reduce network costs and would incur additional migration costs. Relying on Physical Infrastructure defeats the purpose of moving to IaaS in the first place and also can be costlier due to maintenance and staffing requirements.

Correct Answer: Network Security

When a company migrates its entire on-premises infrastructure to an Infrastructure as a Service (IaaS) provider, the primary security aspect to focus on is Network Security. This is because with IaaS, the company is essentially utilizing a virtualized computing resource over the internet. Network Security thus becomes crucial as data is more exposed to potential interceptions during transmission and needs to be protected. The other options, 'Physical Security', 'Hardware Maintenance', and 'Software Licensing', become less relevant as the IaaS provider usually takes care of these aspects. The shift to IaaS will relieve the company from physical server maintenance and worry about hardware. But the company will still have to ensure that all network communications are secured and protected from unauthorized access.

Correct Answer: Use an IaaS provider with a powerful API and user-friendly management dashboard

The best solution for a rapidly growing web hosting company would be to use an Infrastructure as a Service (IaaS) provider with a powerful API and user-friendly management dashboard. This option would enable them to deploy and administer virtual machines quickly and efficiently, which is a critical need for the company at this point. This option also allows for scalability as the company continues to grow. The other options aren't optimal. Increasing their on-premises server hardware may be costly and time-consuming, and it might not provide the flexibility or scalability the company needs. Migrating to a Software as a Service (SaaS) platform for website management may not provide the level of control over the infrastructure that they need. Purchasing dedicated servers from a third-party provider may also be inflexible and may not provide the scalability and control they need.