Hello and thanks in advance!

In a single Excel sheet: I have a column (A) of city names and a column (B)
of state names (about 3100) generated from an internal company db. I need to
check for the "correct" spelling of these city and state names by comparing
each row in these columns to a master list of city and state names (about
29000) located in columns D and E, respectively, a list from a third party
resource.

SOOO, I believe I need a formula and/or logic to first see for each row if
the city and state in A and B match ANY city and state in columns D and E. If
so, no action should be taken or at most a Y indicator put in column C. If
not, then I would like the formula or logic to check the city and state name
from A and B to those found in D and E for the closest match and then suggest
that closest match in column C in that same row. It needs to take into
consideration two word city names (and spaces) and the state names need to
match.

Thanks!