Question

what method would separate a mixture of iron filings and sugar most efficiently?
dissolve the sugar in water, then filter the iron out, then evaporate the water.
add the iron and sugar to water; decant the sugar water and then evaporate it.
pick the iron filings out by hand.
use a magnet to attract the iron.

Explanation:

Iron is ferromagnetic, meaning it is attracted to magnets, while sugar is not magnetic. This method directly separates the two components in one simple step, which is far more efficient than dissolving/filtering, decanting, or hand-picking, which are more time-consuming or require multiple steps.

Answer:

D. Use a magnet to attract the iron.