option strict disallows implicit conversions from system.object to string

I have both option strict and option explicit turned on in my project. When i build it i get the following error:

" option strict disallows implicit conversions from system.object to string"

I am getting this error for the piece of code below:

            If DataReader.Read() Then

                PersonCheckingOut.Text = DataReader("NameCheckingOut") 'on this line
                Reason.SelectedValue = DataReader("ReasonCheckedOut")  'on this line
                TesterName.Text = DataReader("TesterUsedOn")                 'and on this line as well..

           end if

What is the solution for this?