Right choice is (c) preparative
The best I can explain: Purification is classified into preparative or analytical. Preparative purification is targeted towards producing large quantities of purified proteins which are of commercial important. Examples which are purified by the preparative technique are laccase, insulin, HbS Ag, etc. Analytical purification is used to produce small scale lab production of purified proteins. Ultrafiltration and chromatography are the steps involved in purification.