A is proportional.
Lets simplify the problem,
← divide numerator/ denominator by 4
= 4/20= 1/5
Thus A form a proportion
≠ 1/5
Thus B is not a proportion
← divide numerator/ denominator by 4
= 2/5 ≠ 1/5
Thus C is not a proportion
5/1 ≠ 1/5
Thus D is not a proportion
A is proportional.
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