It looks like you have to put together a small portfolio of diversified stocks. That's a fun assignment!
First, my advice is based on what I've taught using the Stock Market Game and the Gen I-Revolution online finance games. It looks like the game portal your teacher is using is similar. I typically recommend diversifying with a combination of mutual funds, fixed-income securities like United States Treasury Bills, mid-cap stocks, and large-cap stocks. Non-cyclical stocks are also a good bet. These are basically stocks that aren't overly affected by market fluctuations. They do well whether the economy is buoyant or tanking (within limits). Examples of non-cyclical stocks are food and utilities stocks from companies like General Mills, Proctor and Gamble, Coca Cola, and Duke Energy. Take a look at top performing utilities stocks here.
Compare the list to the top electric utilities stocks of 2016.
Whatever you decide to invest in, remember to check the latest news and updates about the stocks you are interested in. Also, choose utilities or non-cyclical stocks which pay out dividends. It's always a good bet!
Read about cyclical and non-cyclical stocks here.
While we're on the subject of stocks which pay out dividends, here are some larger-cap companies that you may want to include in your portfolio: Apple, Johnson & Johnson, and AT&T. Here are the rest of the ten dividend stocks to buy in September 2016. Each listed stock comes with an explanation of why you should purchase it. Pay close attention to dividend payouts, EPS (Earnings Per Share), and P/E Ratios. Remember to look up the same information for November 2016 for the ten companies before you decide to include them in your play portfolio.
With fixed-income securities, you're lending money to the federal government. At a fixed later date, the U.S. government is supposed to return your principal investment along with a set interest. That's a great investment!
However, one caveat: U.S. Treasury Bills once considered traditionally safe investments are now in danger of becoming less so. To illustrate, the current 10-year yield is at a paltry 1.6%. Even though that's compounded, you may lose purchasing power after ten years. Whatever you do, try to keep up with current events; it's key to good investment. Read the article: The World's Safest Investment Just got More Dangerous.
I hope this helps!