'Yammer' means to talk repetitively, whine, or complain persistently - lamenting or grumbling loudly. Option A (strike) means hitting - unrelated to vocal complaining. Option B (lament/grumble) directly captures the complaining, whining nature of yammering. Option C (whimper) is more quiet/weak sounding, while yammering is typically loud and persistent. Option D (shiver) means trembling from cold/fear - completely unrelated. Yammer is specifically about vocal complaining.