Choice "C" is correct. Among other events, a partnership terminates for income tax purposes when 50% or more of its interests change hands within 12 months. That threshold was reached for Able on December 20, at which time the partnership terminated for income tax purposes.Choice "b" is incorrect. On February 4th, only 30% of the interests in the partnership changed hands.Choice "a" is incorrect. The end of the taxable year is not the termination date, rather it is the date on which the actual sale or other terminating event occurs.Choice "d" is incorrect. The partnership does terminate when 50% or more of its interests change hands within 12 months.