The United States of America _____one of the most developed countries in the world.

The United States of America ________ one of the most developed countries in the world.
 A. is         B. are         C. was          D. were

The United States of America _____one of the most developed countries in the world.

1. A.
   is
2. B.
   are
3. C.
   was
4. D.
   were

The United States of America _____one of the most developed countries in the world.

 A. is                    B. are               C. was           D. were

. The United States of America___one of the most developed countries in the world.

A.is                      B.are             C.was              D.were