The correct answer is a) a class or category of objects, events, or activities.
The concepts are ideas that represent a class or category of objects, events, or activities.
In general terms, we can define a concept as an idea or a form of though. It is the general idea that comes to your mind before identifying with words. Concepts can be a class or category of objects, events, or activities that are formed in your brain to understand things. The abstract idea that is formed in your mind can be understood and apply to many different to understand reality.
The Church tends to have the most traditional ideal. This sounds like the time period of enlightenment and using ideas of Romanticism to justify marriage.
