Final answer:
Overextending or misplacing hair extensions results in loose hair. Proper tension is vital for extensions to secure properly and blend well. The correct balance ensures comfort and natural appearance.
Step-by-step explanation:
Overextending or misplacing the beginning of the extension can leave the hair loose (Option C). When applying extensions, proper tension is vital to ensure that they are neither too tight, which can cause discomfort or damage to the hair and scalp, nor too loose, which can result in the extensions failing to secure properly to the natural hair. A balanced tension ensures that the extensions will hold correctly and blend seamlessly with the natural hair.