Which of the following statements about the application of the collateral source rule to benefits gratuitously received is correct? Question 4 options: a) At common law a defendant was not allowed to introduce evidence that a benefit received by the plaintiff was gratuitously provided. b) Under modern law defendant is not allowed to introduce evidence that a benefit received by the plaintiff was gratuitously provided. c) Medicare benefits, but not Medicaid benefits, are treated as gratuitous benefits. d) None of the above is correct