What is this paragraph’s topic sentence? in 1867, the united states bought alaska from russia for about $7 million. many americans thought it was a foolish purchase. they thought alaska was a wasteland of ice and snow. however, alaska is rich in oil, fish, and lumber. the purchase of alaska was a true bargain. a. however, alaska is rich in oil, fish, and lumber. b. many americans thought it was a foolish purchase. c. the purchase of alaska was a true bargain. d. in 1867, the united states bought alaska from russia for about $7 million.