Which sentence contains a supporting detail that answers the question when? 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. many americans thought it was a foolish purchase. b. the purchase of alaska was a true bargain. c. in 1867, the united states bought alaska from russia for about $7 million. d. however, alaska is rich in oil, fish, and lumber.