I need help with bit strings in discrete mathematics!

Suppose U be the universal set. Then determine the bit strings for the following: a. An empty set b. Universal set,U c. Symmetric difference of two sets which are subset of universal set, U(The symmetric difference of A and B, is the set containing those element in either A or B, but not in both A and B.) d. Union of n sets that all are subsets of the universal set, U e. Intersection of n sets that all are subsets of the universal set, U Define any variables (such as name of the sets, size of the universal set or the bitstring length, etc), state any assumptions and provide brief justification or explanation of the derivation of each of the above bit strings. (Provide general case answer and not example specific answer for all including justification)