Correct option is C
· A flip-flop whose state changes on the rising or falling edge of a clock pulse is called an edge-triggered flip-flop.
· An edge-triggered flip-flop is a type of flip-flop that changes its state only at the moment of a specific transition of the clock signal, either from low to high (rising edge) or from high to low (falling edge).

· This is in contrast to level-triggered flip-flops, which can change state whenever the clock signal is at a particular level (high or low).
· An edge-triggered flip-flop change states either at the positive edge (rising edge) or at the negative edge (falling edge) of the clock pulse on the control input.
· A positive edge triggered flip flop transfers data from input on the low to high transition of the clock pulse.
· A negative edge triggered flip flop transfers data from input on the high to low transition of the clock pulse.
