A dress on sale in a shop is marked at $D. During the discount sale its price is reduced by 25%. Staff are allowed a further 20% reduction on the discounted price. If a staff member buys the dress what will she have to pay in terms of D ?	Choose the correct choice:
A) 0.6 d B) 0.7 d C) 0.5 d D) 0.8 d E) 0.9 d

Rationale: "effective discount = a + b + ab / 100 = - 25 - 20 + ( - 25 ) ( - 20 ) / 100 = - 40 sale price = d * ( 1 - 40 / 100 ) sale price = . 6 * d answer ( a )"
Answer: A