Which of the following is NOT a type of CPU core?

The term "Octa-type" does not represent a recognized or widely accepted category of CPU core like the other options do. In the realm of CPU architecture, core types generally refer to the number of individual processing units or cores within a single CPU. A single-core CPU has one core, a quad-core CPU has four cores, and a hexa-core CPU has six cores, all of which are standard terms used in processor specifications to indicate the multitasking ability and performance capabilities of the CPU.

The other options represent established configurations that are commonly found in modern processors. A single-core processor was more typical in earlier computer designs, while quad-core and hexa-core options have become prevalent as processing demands have increased. The term "octa-core" refers to CPUs containing eight cores, which is another recognized configuration. Thus, "Octa-type" does not conform to any standard terminology regarding CPU cores, making it the correct choice for the question posed.