Coca-Cola's stock has pulled back enough to make the 3.1%-yielding shares look attractive for long-term investors.Coca-Cola (KO 0.65%) is one of the largest consumer staples companies on the planet. It has an iconic name, which it shares with its top product. If you are worried about the lofty level of the S&P 500 index (^GSPC 0.34%) today, Coca-Cola's valuation is actually rather attractive. But the real reason for you to trust this company can deliver is actually more fundamental.What does Coca-Cola do so ...