Answer:
Option B: 0.4
Explanation:
We have 20 dots.
Such that each column represents the repetitions for each proportion.
So:
0.1 -> 3 times
0.2 -> 1 time
0.3 -> 4 times
0.4 -> 6 times
0.5 -> 3 times
0.6 -> 3 times
Now we can compute the mean of these values, and that will be the best estimation we can make with the given data.
Remember that for a set of N values:
{x₁, x₂, ..., xₙ}
The mean is:

In this case we have the set of 20 points described above, then the mean is:

Rounding to the first place after the decimal point, we get:
M = 0.4
Then the correct option is option B.