Final answer:
When distinguishing synthetic wigs from human-hair wigs by testing a strand with a match, a synthetic fiber will melt and form a hard bead (Option 1). It is due to the high-temperature manufacturing processes like pyrolysis, unlike human hair which will burn and turn to ash.
Step-by-step explanation:
When tested with a match, a synthetic fiber will melt and form a hard bead.
This occurs because synthetic fibers are made through processes like pyrolysis, which involves heating a precursor polymer to decompose it into a fiber form.
These fibers, such as those made from Orlon (polyacrylonitrile) or polydimethylsilane for silicon carbide fibers, are not low-melting and thus react to high heat by melting.
Comparatively, human hair, being composed of keratin, a natural protein, will burn and produce a strong odor and generally turns into ash when burned with a match, instead of melting.
Hence, the correct answer is Option 1.