How is a "conundrum" best described?

A "conundrum" is best described as a difficult problem. The term is often used to refer to a situation or dilemma that is challenging to solve, typically involving complex issues or perplexing scenarios that require careful thought and consideration. The essence of a conundrum lies in its intricacy and the mental engagement it demands from an individual to arrive at a solution.

In contrast, other options do not capture the true nature of a conundrum. For example, characterizing it as a trivial question does not reflect the depth and seriousness of a conundrum, while describing it as a light-hearted riddle suggests a playful context, which may not always align with the complexity typically associated with a conundrum. Finally, identifying it as a straightforward situation contradicts the inherent challenge and complication that defines a conundrum. Therefore, “a difficult problem” accurately encapsulates the meaning and connotation of the word.