Which of the following best defines a "bastion"?

The term "bastion" refers to a stronghold or fortification that provides protection and support for specific ideas, values, or principles. In this context, choosing an option that encapsulates the idea of defense is crucial. The correct answer connects to the notion of safeguarding and promoting particular principles, making it the most fitting definition.

A bastion serves as a metaphor for an institution or entity that actively defends and upholds its core beliefs or practices in the face of opposition or challenge. This aligns perfectly with the idea of an institution dedicated to preserving certain philosophies, whether they be political, social, cultural, or ideological. The other options do not embody this concept sufficiently, as they either imply negative qualities or lack the aspect of defense and support that characterizes a bastion. Thus, the emphasis on promoting and protecting specific principles makes this definition the best choice.