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You can calculate them out and check which one is the most accurate
so if one of the choices was 1/3 of 50, then you would do:
1/3 in the calculator (should be 0.333...) times 50
And you can compare it with the EXACT number, which is:
0.25*53=13.25
This way you can test all the options
C=(-10;5). If you want an explanation I would be happy to explain it