To choose the best option for improving the line of best fit for the data plot, consider the overall trend of the data points. Since I don't have access to a visual plot, I can guide you based on common practices.
If the trend in the data is positive (increasing), then making the line steeper or less steep would not generally be advisable unless it's to align with more points. If the data appears to be negatively correlated, then a negative slope would be appropriate.
However, the most practical option among the responses given tends to be about positioning the line accurately to represent the center of the data.
The best choice would likely be: Keep it parallel and move it up through the center of the data.
This option suggests adjusting the line's position to reflect the overall trend of the data more accurately without altering its slope drastically.