Tuttle died at age 76, leaving a will that she

Tuttle died at age 76, leaving a will that she made at age 40 that provided that her estate would be distributed to her three children (Anna, Bill, and Charles). Two years after the time of the execution of the Will, Tuttle had given birth to another child named Donald. 

a. If Tuttle dies who inherits her estate? (Explain) 

b. What is the name that we give to the status of Donald? 

c. What if Charles dies before Tuttle, If the will states that the beneficiaries take “per stirpes”, what happens to the share of Charles?