By Lisa Richwine and Ronald Grover LOS ANGELES (Reuters) – Netflix Inc added more than 2.3 million U.S. customers in the fourth quarter, sending its shares up 17 percent in after-hours trading, and said it was testing different pricing plans for its monthly TV and movie streaming service. Earnings-per-share were 79 cents, Netflix said in a statement, beating the 66 cents average forecast of analysts surveyed by Thomson Reuters I/B/E/S. The strong U.S. subscriber growth, a closely watched barometer of company performance, came in at the top end of Netflixs forecast range. Netflix also signed up 1.74 million new customers in foreign markets, bringing its worldwide total to 44.4 million. Answering critics who question how big Netflix could grow, the company said it expected to add more U.S. subscribers in the first quarter of 2014 than in the year-ago period.