Bob just had a baby boy today. He is thinking about starting a savings account for his son's college fund. He thinks his son will need around $150,000 (will be withdrawn when he is 18 years old). The current interest rate is 3.5%/ year. (a) If Bob just wants to put one lump sum into this account today, how much does he need? (b) If Bob wants to put an equal amount of money into this account every year, how much does he need a year? (c) If Bob wants to put an equal amount of money into this account every month, how much does he need a month