John has a general power of appointment over his father's assets. Which of the following is not true regarding such a power?

Select one:

a. John can appoint his father's money to pay for the needs of his father.

b. John can appoint money to John's creditors.

c. John must only appoint money using an ascertainable standard.

d. If John predeceases his father, John's gross estate would include his father's assets even though they had not been previously appointed to John