A close friend approaches you and asks for some help devising their personal investment policy. They are 45 years of age and have twins that are currently 15 years old. They are really proud of their children and tell you that they both plan to become doctors and train abroad when they graduate high school, and that they plan to fully fund their children's university education. They plan to retire at 65, they have a lovely home that still has quite a sizeable mortgage attached to it. They currently have $250,000 to invest after having recently sold their small business. They have since started a new job working for the public service, which will produce a very stable income stream with no real risk of job loss. This job stability is quite important because your friend had been concerned about the fluctuations of the business performance in the past because they are really quite conservative in many aspects of their life. What factors do you identify as being important in determining the optimal portfolio? What sort of mix between stocks, bonds, and cash would you recommend? Justify your answer.