B, heat, is the correct answer. Heat is represented by a capital q in thermodynamic equations.
Steel is more elastic than rubber<span> because </span>steel<span> comes back to its original shape faster </span>than rubber<span> when the deforming forces are removed, hope it helps :)</span>
Pour the entire components into water.
First the iron filings can be separated using a magnet as iron is a magnetic element.
By pouring the mixture into water, it allows the salt to dissolve in the water, while the sand will not.
Next we can run this solution through a filtration device to separate the sand from the water.
Now all that's left is to let the water evaporate so that the salt will be exposed that dissolved into the water.