A flame-retarded fabric is best suited for clothing items that need to be resistant to fire, such as those that may be exposed to flames or heat sources. This makes it particularly important for clothing that is designed for children, who may be more likely to accidentally come into contact with fire, and for clothing that is worn in situations where there is a higher risk of fire, such as in certain work environments or for certain activities.
Therefore, among the options listed, a flame-retarded fabric is best suited for children's apparel. It can also be suitable for other clothing items depending on their intended use and level of risk, but children's apparel is the option where it is most important to prioritize fire resistance.