Answer:
A) $1,000: the constructive receipt doctrine states that if the income is not subject to limitations or restrictions, then it should be taxed as soon as it was available, not necessarily when it was received.
B) $100: he only received $100, this year, the rest was given to him on the following year.
C) $1,000: since Clyde received the mail before the end of the year, the constructive receipt doctrine applies.
D) $0: the constructive receipt doctrine does not apply due to the restriction of the check being postdated.