Colin would like to use his recent inheritance of $200,000 to establish a charitable remainder trust. Colin would like to have the flexibility to make additional contributions to the charitable remainder trust in the future. Which of the following would you recommend for Colin? (a) A Charitable Remainder Annuity Trust. (b) A Charitable Gift Annuity. (c) A Charitable Lead Unitrust. (d) A Charitable Remainder Unitrust