Darren and Gabriella are a young working couple raising their 2 pre-school children. Darren is an entrepreneur and his auto-body franchise business is just starting to take off. He expects that his business will continue to excel and he projects that his income will continue to rise by 6% or more a year. Gabriella is a realtor who works out of her home office. Neither Darren nor Gabriella have employer plans or group coverage and they approach you about disability insurance. While Darren determines that he can currently afford a premium of $200 per month, he believes that he will be able to afford more as his business excels and his income rises. You discuss riders that can be added to the policy to tailor to their future insurance needs. Which of the following is the BEST option for Darren and Gabriella in this scenario?

a) cost of living adjustment

b) future purchase option

c) residual disability benefit

d) waiver of premium