Rex borrowed $20,000 @ 12.6% (flat rate) p.a. for 5 years to buy a car. Repayments are for interest only. His records show the car is used 75% in the course of his employment. Calculate the allowable deduction in each of the following situations where the loan was taken out on 1 July of the current income year and the first repayment was made on the same day in the following situations: 

(a) Rex pays monthly for the whole year. 

(b) Rex pays monthly, and then on 1 May CY pays for 4 months. 

(c) Rex pays monthly and then on 1 January CY pays for 8 months. 

(d) Rex pays monthly, and then on 1 May CY pays for 16 months. Calculate your answer if Rex was a non-SBE business owner and an SBE taxpayer who had elected to use the prepayment option.