Q24: For the last five years the Dutch economy has grown

Q24:

For the last five years the Dutch economy has grown faster than Britain, France, or Germany, with the unemployment rate having remained well below that of the other three countries.

A. Britain, France, or Germany, with the unemployment rate having remained

B. have those of Britain, France, or Germany, and the unemployment rate remaining

C. have Britain, France, and Germany, and the unemployment rate has remained

D. the economy of Britain, France, and Germany, with the unemployment rate that has remained

E. the economies of Britain, France, and Germany, and the unemployment rate has remained

I chose E,
Iam not questioning the answer but I am not sure why "economy" here can take the Plural form??