Company A has a SaaS cloud that hosts their office suite software. Company B has an IaaS cloud that provides all their server hardware, including the server hosting their office suite software. Which

A defining characteristic of cloud infrastructure, whether SaaS or IaaS, is the inclusion of enterprise-grade disaster recovery features such as offsite backup synchronization with a hot site. Company A's SaaS provider and Company B's IaaS provider both maintain replicated backup data at a secondary site to ensure business continuity - this shared cloud infrastructure benefit applies equally to both service models.

Servers being on-site is false for both companies - SaaS and IaaS clouds locate resources in remote provider data centers, not on customer premises.

Software being hosted is a defining characteristic of Company A's SaaS model, but in Company B's IaaS model the provider only supplies hardware - Company B is responsible for installing and managing the office suite software itself, so this is not equally true of both clouds.

Server clustering is an implementation detail that is not guaranteed or definitionally shared between SaaS and IaaS service models.