Final answer:
Adding pulverized toasted nuts to a meringue makes it chewy while maintaining some fluffiness, if folded in properly. It will not cause the meringue to collapse or turn sour.
Step-by-step explanation:
When you add pulverized toasted nuts to a meringue, the nuts introduce fats and oils, which can potentially disrupt the structure of the whipped egg whites. However, when done correctly, the nuts are usually well folded into the stable meringue, creating a balance between the chewy texture from the nuts and preserving some of the meringue's fluffiness. Therefore, the correct answer is b) Becomes chewy. It won't collapse if the nuts are carefully folded in, nor will it turn sour as the chemical composition of nuts does not induce sourness.