Answer :

To determine what percentage 20 is of 50, follow these steps:

1. Understand the question: We need to find out what percent 20 is when compared to a whole of 50.

2. Set up the formula for percentage:
[tex]\[ \text{Percentage} = \left( \frac{\text{Part}}{\text{Whole}} \right) \times 100 \][/tex]
In this context, the part is 20 and the whole is 50.

3. Substitute the numbers into the formula:
[tex]\[ \text{Percentage} = \left( \frac{20}{50} \right) \times 100 \][/tex]

4. Simplify inside the parentheses:
[tex]\[ \frac{20}{50} = 0.4 \][/tex]

5. Multiply by 100 to find the percentage:
[tex]\[ 0.4 \times 100 = 40 \][/tex]

6. Present the final result:
[tex]\[ 20 \text{ is } 40 \% \text{ of } 50 \][/tex]

So, the best answer is:

A. [tex]$40\%$[/tex]