Understanding 'Conundrum' in Context

During the historical seminar, the speaker discussed the conundrum faced by early explorers. These individuals often had to navigate uncharted territories while confronting not only the unknown nature of the lands ahead but also the societal expectations that constrained their ambitions. The struggle to prioritize personal aspirations against the duties to their sponsors presented a significant dilemma for many.

In this context, the term 'conundrum' most closely aligns with which of the following words?