On September 30 Partner C buys 12 of partner As interest in the equal AB calendar- year partnership, so A and C each own 25% after the sale. For the year, the partnership earns income of $2,000 a month for January through August, and $6,000 a month for September through December. How much income will A and C each have from the partnership under (a) the interim closing method and (b) the proration of partnership income method?