4. Given the laser-based distance measurer’s FSM and datapath below, assume all gates have a delay of 3 ns, the 16-bit up-counter has a sequential delay of 5 ns, the state register and 16-bit register each have a sequential delay of 3ns, the shifter has a sequential delay of 1ns, and wires have no delay. Also assume the setup time for each sequential component (state register, counter, and register) is 1ns. Determine the critical path for the laser-based distance measurer.