A deceased individual owned a bond. Which of the following is included in the estate principal?

  a. All interest collected prior to distributing the bonds to a beneficiary is considered part of the estate principal.
  b. Only the first cash payment after death is included in the estate principal.
  c. Interest that was not collected prior to death is excluded from the estate principal.
  d. Interest earned prior to death is considered part of the estate principal even if received after death.