For a 4340 steel alloy, describe continuous-cooling/tempering heat treatments that would be required to produce specimens having the following yield/tensile strength - ductility property combinations:
a) Tensile strength of 1100 MPa, ductility of 50% RA.
b) Yield strength of 1200 MPa, ductility of 45% RA.
c) Tensile strength of 1300 MPa, ductility of 45% RA.