What is the san rogue river and what is its relationship to the columbia river

The correct answer to this open question is the following.

The San Rogue River is located in Southwest Oregon, close to the Crater Lake.  It runs 215 miles from the Cascade range to the Pacific Coast. It is a beautiful river with rapids and it is full of Salmons.

The Columbia River starts in the Rocky Mountains in the province of British Columbia, Canada. It is the largest river in the Pacific Northwest region. Its relationship with the Rogue River is that when the Columbian River bends to the west in the state of Oregon, its waters become part of the Rogue River.

i believe the correct answer is option b. most eastern european nations joined nato.

though i could be wrong, option d. the eastern european nations were granted complete independence, would be another choice.

hope this ! : )