All the options listed can be considered APIs, but the most notably recognized as an "API" in the traditional sense would be the Google Maps API.
- NumPy API and SciPy API refer to the application programming interfaces of the respective libraries for Python, but they are usually referenced more in the context of the libraries themselves rather than as standalone APIs.
- C++ API could indicate any number of APIs developed in C++, but is also somewhat vague without a specific context.
Overall, the Google Maps API is the most widely recognized option among the choices presented.