Four years ago, Glenda purchased disability insurance coverage providing a $3,000 monthly benefit. Glenda financially qualified for $4,000 a month, but budget constraints limited her to only being able to afford $3,000 at the time. Recently, Glenda paid off the debts that formerly limited her budget and would now like to increase her disability coverage. Glenda had originally purchased a rider that now allows her to increase her coverage to $3,600 a month without being subject to medical underwriting. What rider did Glenda purchase? a) A cost-of-living adjustment rider. Ob) A future purchase option rider. c) A residual disability benefit rider. d) A return of premium rider