You lift a suitcase from the floor and keep it on a table. The work done by you on the suitcase does not depend ona) the path taken by the suitcaseb) the time taken by you in doing soc) the weight of the suitcased) your weight

Our system consists of the suit case and the earth. work done by you = change in K.E. of the system + change in P.E. of the system. Now, change in K.E of earth = 0 change in K.E. of the suitcase = 0, change in P.E. of the system = mgh where m = mass of the suitcase, h = height of table. Since gravitational force is a conservative force, work done does not depend upon path. Also work done does not depend upon the weight of the person who is doing work. Time determines the average power delivered  by the person but the work done is independent of the time.