If a data point is way off the trend line, which of the following will not resolve the problem?

There are no stated solutions. However, deleting the outlier in your data is not a good idea, especially if the data point which seems to be an outlier isn't there due to a statistical error or error in sampling, but is actually there because it is a valid result. 

If you were to delete this data point, it would mean you would delete a valuable and interesting aspect of your data which might be crucial for further research.