Let's compute the returns after 1 year, including taxes.
Tax free bonds:
Only 30% of the income is taxed at the 35% tax rate! (That's because of the "Dividends-Received Deduction". Reference: http://www.investopedia.com/terms/d/dividendreceiveddeduction.asp)
The preferred stock looks to be the best option.
Let me know if you have any questions,