Lisa is in her mid-20s. She just found a secure job as a middle school teacher. Her investment in the tax-deferred retirement account will be her most important savings for retirement. Which one of the followings is the best investment strategy in her retirement account during the next 40 years before she retires? Invest all her retirement savings in stocks throughout the next 40 years. Invest all her retirement savings in bonds throughout the next 40 years. Invest all her retirement savings in stocks during early years and then gradually shift to bonds. At the time of retirement, most of the savings are in bonds. O Invest all her retirement savings in bonds during early years and then gradually shift to stocks. At the time of retirement, most of the savings are in stocks.