68) The unit of a computer system which executes program, communicates with and often controls the operation of other subsystems of the computer is the

69) The register which holds the address of the location to or from which data are to be transferred is called

70) The register which contains the data to be written into or read out of the addressed location is called

71) Which of the following is used as storage locations both in the ALU and the control section of a computer

72) The register used as a working area in CPU is