How many types of patents are there?

The correct answer indicates that there are three types of patents: Utility, Design, and Plant.

Utility patents are the most common type, protecting new and useful processes, machines, articles of manufacture, or compositions of matter, or improvements thereof. They are aimed at inventions that have a functional aspect.

Design patents protect the ornamental design of a functional item rather than its utility. They cover the appearance and aesthetic aspect of an item, making this type of patent distinct from utility patents.

Plant patents apply to new and distinct varieties of plants that have been asexually reproduced. This category addresses biological inventions that are not covered under the utility and design patent types.

While other options may refer to provisional and international patents, these do not represent distinct types of patents in and of themselves. A provisional patent application is a temporary measure to establish an early filing date but does not itself lead to a patent grant. An international patent system facilitates obtaining patent protection in multiple countries but does not constitute a separate type of patent. Thus, the answer accurately reflects the formal categories recognized by the United States Patent and Trademark Office.