To calculate the distance covered by an object traveling at a consistent velocity, you can use the formula:
\[ \text{Distance} = \text{Velocity} \times \text{Time} \]
Given that the velocity is 20 m/s and the time is 4 seconds:
\[ \text{Distance} = 20 , \text{m/s} \times 4 , \text{s} = 80 , \text{m} \]
So the correct response is:
80 m