A woman made a will leaving the residue of her estate to her son, who is also her sole executor. There is no substitutionary gift of residue. Her son was one of two witnesses to the will.Which of the following correctly states the position with regard to the administration of the estate?
选项：

A:The estate will pass under the intestacy rules and may not be administered by the woman's son. incorrect
B:The estate will pass under the will but the woman's son will be required to appoint an alternative executor as he witnessed the will. incorrect
C:The residue will pass under the intestacy rules although the woman's son may administer the estate. correct
D:The woman's son may benefit from the will but may not act as executor and must apply for a grant of letters of administration with the will annexed. incorrect
E:The woman's son may not benefit from the will or act as executor and the will is therefore invalid. incorrect