Which word suggests something that is supported or upheld?

The choice of "sustained" effectively conveys the idea of something that is supported or upheld. The word suggests a continuous or steady state, indicating that something is not only held up initially but maintained over time. This aligns with the concept of support, as it reflects the ongoing nature of sustaining something, whether it be an idea, condition, or physical structure.

While "uphold" clearly indicates the act of supporting or maintaining something, and "fortified" implies that something has been made stronger or more secure, they carry slightly different connotations. "Endorsed" involves giving approval or support, but it does not explicitly suggest the concept of being upheld in a physical or continuous sense.

Therefore, "sustained" is the most fitting response as it captures the essence of something being supported over an extended duration rather than just in a moment or by affirmation.