4.2 Under this ADD Rd, Rs, Rt instruction, which blocks perform useful function. Select from the blocks below. I-memory (Instruction memory) Registers (register file) ALU add (Branch adder) 4.3 If this ADD Rd, Rs, Rt is the only instruction to be supported by the processor, what is the clock cycle time (in ps)? Use the latency of each block below. I-memory 200 ps registers 90 ps ALUmux = 20 ps Regmux = 20 ps ALU - Data-memory 250 ps = 90 ps 4.4. What is the clock rate in G Hz (giga Hertz) in 4.3