$$I$-$Mem$/$D$-$Mem$$ is the amount of time to access the Instruction or Data Memory.

$$Register File$$ is the amount of time to read rs$1$ and rs$2$ after a rising clock edge.

$$PC Read$$ is the amount of time needed after a rising clock edge for the new PC value to appear on the output; this delay value applies to the PC only.

$$Register Setup$$ is the amount of time a register$$s data input must be stable before a rising clock edge; this delay value applies to both the PC and Register File.

$$Control$$ is the total amount of time for the Control unit and the ALU control unit to produce the $4-$bit $$ALU operation$.$