You need to separate a mixture of iron filings, sand, and salt. which of the three would be easiest to separate first and what method would be best? a) the salt would be easiest to separate, and using a magnet would be the best method. b) the iron filings would be easiest to separate, and using a magnet would be the best method. c) the salt would be easiest to separate, and using hot water to dissolve the other substances would be the best method. d) the sand would be easiest to separate, and using hot water to dissolve the other substances would be the best method?