Final answer:
The corrected text should include two commas: On March 19, 2014, the University of Southern California purchased a letter written by Lewis Carroll, author of Alice's Adventures in Wonderland, for $19,959.
Step-by-step explanation:
The corrected text with two commas inserted should read:
On March 19, 2014, the University of Southern California purchased a letter written by Lewis Carroll, author of Alice's Adventures in Wonderland, for $19,959.
The sentence can be combined by completing the relative clause like this: Ann Curry, who was rescued by Boy Scout Troop 368 when she broke her ankle while hiking in New York's Harriman State Park, is a television journalist.