SUMIFS Function

Please try:

=SUMPRODUCT(--(D:D="Zloty") + --(D:D="GBP"))*C:C

If you want conversion, multiply to the one you want to change (formula below converts Zloty to GBP):

=SUMPRODUCT(--(D:D="Zloty")*(.19/1.00) + --(D:D="GBP"))*C:C

Hope this works