The core challenge is interpreting "least [blank] was also the most sought after" as a "contradictory relationship." This implies the blank must be a positive quality. If an artist has the least of a positive quality (i.e., they are unfriendly), and are still "most sought after," that's the contradiction.

Among the choices, C. cordial (meaning warm and friendly) is the only positive quality. Being "least cordial" means being unfriendly, which creates the required contradiction.