For two ratios to be equivalent, its means and extremes if multiplied must be equal to each other.

Let's start with Option A.

Since they are equal, then Option A is equivalent to 4/5.
Let's check Option B.

Let's check Option C.

Let's check Option D.

Let's check Option E.

FInally, let's check Option F.

Hence, only Option A, Option C, and Option E are equivalent to ratio 4/5.