Task: Question Answering
Input (English): Problem: a certain pair of used shoes can be repaired for $ 11.50 and will last for 1 year . a pair of the same kind of shoes can be purchased new for $ 28.00 and will last for 2 years . the average cost per year of the new shoes is what percent greater than the cost of repairing the used shoes ? 
Options: a ) 20.8 , b ) 21.46 , c ) 21.74 , d ) 22.3 , e ) 21.4
Output (English): c