Which approach should you recommend?

You have an existing SharePoint 2010 solution consisting of custom Web Parts deployed to the global assembly
cache (GAC). The signing key used for the Web Parts has recently changed. You need to design an update to the
Web Parts without any change to the value settings of their properties.
Which approach should you recommend?

A.
Deploy the changes within a SharePoint solution.

B.
Copy the changes directly to the GAC and perform an IISReset.

C.
Programmatically copy the information from the existing Web Parts to their new versions and then remove the old instances.

D.
Update the Web Parts through the Web Part gallery and select the Overwrite if file already exists check box.