Task: Question Answering
Input (English): Problem: a retailer bought a machine at a wholesale price of $ 90 and later on sold it after a 10 % discount of the retail price. if the retailer made a profit equivalent to 20 % of the whole price, what is the retail price r of the machine ?
Options: a. 81, b. 100, c. 120, d. 135, e. 160
Output (English): c