Consider a fuzzy set old as defined below Old = {(20, 0.1), (30, 0.2), (40, 0.4), (50, 0.6), (60, 0.8), (70, 1), (80, 1)} Then the alpha-cut for alpha = 0.4 for the set old will be

• A. {(40,0.4)}
• B. {50, 60, 70, 80}
• C. {(20, 0.1), (30, 0.2)}
• D. {(20,  0),  (30,  0),  (40,   1), (50,1), (60, 1), (70, 1), (80, 1)}