Comparatively few rock musicians are willing to laugh at themselves, although a hint of_____can boost sales of video clips very nicely.
The sentence states that comparatively few rock musicians are willing to laugh at themselves. Which means most rock musicians are "
not willing to laugh at themselves". It then contrasts this attitude with yet another disposition which involves a "hint of __________" that can boost sales of video clips very nicely. So the word/phrase for the second blank should be "willingness to laugh at oneself".
congeniality is being warm, friendly and affable.
cynicism is a negative word and is too extreme, the willingness to laugh at oneself is nowhere mentioned to be the result of a negative attitude.
embarrassment is again not the same as being willing to laugh at oneself.
willingness to laugh at oneself is not the result of self-doubt, but an attitude resulting from a willingness to be critical of oneself.
self-deprecation is what happens when you willing laugh at your flaws, mistakes or other imperfections. And this is a conscious act. Hence the correct choice.
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