A. Last month I drove to London, Bristol, Leeds and Cardiff.
B. Last month I drove to London, Bristol Leeds and Cardiff.
C. Last month I drove to London Bristol Leeds, and Cardiff.
D. Last month I drove to London Bristol, Leeds, and Cardiff.
A. Last month I drove to London, Bristol, Leeds and Cardiff.
Explanation: The comma goes between the items in your list, but not before 'and'.
Explanation: The comma goes between the items in your list, but not before 'and'.