Which statement is NOT true? Select one: O a. A register file can hold some variables in a computer program O b. The number of registers in a register file must be a power of 2 O c. A register file can only change the state of a register at a clock tick O d. A register file can load a register in the middle of a clock cycle O e. A register file uses a demultiplexer to determine which register to load O F. A register file uses a multiplexer to determine which register to read out