Please answer the following question: Read the article and select the best answer. Article: Steve Jobs, Apple's chief executive, made his first public appearance since going on medical leave six weeks ago, taking the stage at a San Francisco media event to introduce the iPad 2, the second generation of the company's tablet computer. Thin but energetic, Mr. Jobs showed off a thinner iPad. " We've been working on this product for a while and I just didn't want to miss this day," he said. His absence has concerned investors, especially since the group has given no details of his condition. He was diagnosed with cancer in 2004 and had a liver transplant during almost six moths of medical leave in 2009. People close to him said last month his health had been changing. Apple's stock rose more than 2 percent in the minutes after Mr. Jobs began speaking, then gave up some of its gain as he detailed the iPad 2. The iPad 2 will go on sale in black and white versions in the US on March 11 and in 26 other countries, including the UK and Germany, on March 25. The table is Apple's biggest product launch since the iPhone three years ago, and is comparable to the iPhone as the most expected in Apple's history. Most of the improvements in the latest version had been expected, including front and rear-facing video, which allows video conferencing between iPads, Mac computers and the most recent iPhones and iPods, a larger speaker, a faster processor and other upgrades. The iPad 2 is one-third thinner than the original tablet and slightly lighter, with a 9.7-inch touchscreen. It can run movies, books, games and a complete range of applications. In the US it will work with AT&T and Verizon, the top two mobile carriers. The pricing will be the same to the 2010 iPad at its introduction, ranging from $499 to $829 in six models. But Apple dropped prices on the older iPad on Wednesday by $100 across the board. Apple has made the most of its year-long head start in tablets, selling 15,000,000 units of the older iPad last year and taking about 85 percent of the market. Forrester predicted that the iPad 2 would clain 80... Question: Why are the investors of Apple worried according to the text? Options: A: Apple's stock price changes a lot B: Steve Jobs' health condition is not stable C: The iPad 2 has some technical drawbacks D: Apple faces strong competition from other companies.
Answer:
B