Most opera singers who add demanding roles to their repertoires at a young age lose their voices early. It has been said that this is because their voices have not yet matured and hence lack the power for such roles. But young singers with great vocal power are the most likely to ruin their voices. The real problem is that most young singers lack the technical training necessary to avoid straining their vocal cords -- especially when using their full vocal strength. Such misuse of the cords inevitably leads to a truncated singing career. Which one of the following does the information above most strongly support? ['Young opera singers without great vocal power are unlikely to ruin their voices by singing demanding roles.', 'Most young opera singers who sing demanding roles strain their vocal cords.', 'Only mature opera singers can sing demanding roles without undue strain on their vocal cords.', 'Some young opera singers ruin their voices while singing demanding roles because their vocal cords have not yet matured.']