From the isothermal transformation diagram, answer the following question. 800 1400 Eutectoid temperature 700 1200 600 1000 500 800 Temperature (C) Temperature (F) 400 600 300 Mistart) 200 50% 400 MA M(50%) M(90%) 100 200 0 10-1 105 1 10 102 103 104 Time (s) The thermal treatment begins with: 1. a material that has been homogenized at 760 C 2. rapidly cooling to 680 C and holding for 100 seconds (at dotted line) 3. followed by rapidly cooling to 400 C and holding for 1000 seconds 4. then cooled to room temperature The thermal treatment begins with: 1. a material that has been homogenized at 760C 2. rapidly cooling to 680 C and holding for 100 seconds (at dotted line) 3. followed by rapidly cooling to 400 C and holding for 1000 seconds 4. then cooled to room temperature The final microstructure of this material is: [ Select ] % (Select] phase