Assume for 2013 that Don made one transfer involving his granddaughter as follows: Don opened a joint checking account with his granddaughter, with right of survivorship, for her college expenses. Don made an initial deposit of $100,000. During 2013, granddaughter wrote checks on the account to the school for tuition of $15,000 and living expenses of $20,000. What is the amount of the taxable gift for federal gift tax purposes?
a. 0.
b. $6,000.
c. $21,000.
d. $35,000.