Final answer:
Hybrid cloud implementations that combine IaaS, SaaS, and PaaS are commonly referred to as Hybrid Cloud or XaaS (Anything as a Service), although XaaS is a broad term that isn't specifically listed among the options provided.
Step-by-step explanation:
When multiple service models (IaaS, SaaS, PaaS) are combined into a hybrid form in cloud computing, this is commonly referred to as Hybrid Cloud or HaaS (Hardware as a Service). However, among the options provided, HaaS directly isn't listed.
The concept may be misunderstood with the option 'ZaaS', which isn't a standard cloud computing term. Therefore, based on typical nomenclature and industry standards, none of the given acronym options—DBaaS (Database as a Service), HaaS, XaaS (Anything as a Service), or ZaaS—accurately describe the combination of IaaS, SaaS, and PaaS.
Nevertheless, the closest term that is often used to encapsulate the variety of different cloud services is 'XaaS' or 'Anything as a Service'. Therefore option c . XaaS