$\begin{array}{1 1} \text{(a) Concentration is a chemical solid - liquid separation technique, in which mass transfer of a solute from the liquid solution to a pure solid crystalline phase occurs.} \\ \text{(b)Concentration is the process of separating the components or substances from a liquid mixture} \\ \text{(c)The process of removal of the gangue from Ore is known as Concentration} \\ \text{(d)Concentration is a process in which magnetically susceptible material is extracted from a mixture using a magnetic force.} \end{array} $