Please help down below.

The correct answer is B.
A reduction would have the same ratio between the top and the side of the square, it would just be smaller. The original diagram is 20ft x 10ft, so the top is exactly twice the length of the side (a ratio of 2:1).

The ratio of answer A is not exactly 2:1, so it is not the correct answer.

Answer B is a 2:1 ratio and is SMALLER in size (convert inches into feet...10ftx5ft)

Answer C: it has a ratio of 2:1, but if you convert it from inches to feet you see that it is the SAME exact size as the original...20ftx10ft

Answer D: it is a ratio of 2:1, but it is 40ftx20ft, so it is LARGER than the original one.

Since answer B has the same ratio as the original, and it is the only one smaller in size, that is the correct answer.

Yo no me sé esa mala mia