Your client Sally, age 30, is designing an educational investment program for her 8-year-old son. She expects to need the funds in about 10 years when her AGI will be approximately $70,000. She wants to invest at least part of the funds in tax-exempt securities. Which of the following investment(s) may yield tax-exempt interest on her federal return if the proceeds were used to finance her son's education?
1) Treasury bills
2) EE bonds
3) GNMA funds
4) Zero coupon Treasury bonds