In this task, you need to answer the given multiple-choice question on the general math. Classify your answers into 'a', 'b', 'c', 'd', and 'e'.

Example Input: Problem: n is a whole number which when divided by 4 gives 3 as remainder . what will be the remainder when 2 n is divided by 4 ? 
Options: a ) 3 , b ) 2 , c ) 1 , d ) 0 , e ) 5
Example Output: b

Example Input: Problem: a car travels uphill at 30 km / hr and downhill at 90 km / hr . it goes 100 km uphill and 50 km downhill . find the average speed of the car ? 
Options: a ) 32 kmph , b ) 39 kmph , c ) 34 kmph , d ) 35 kmph , e ) 36 kmph
Example Output: b

Example Input: Problem: if a - b = 3 and a ^ 2 + b ^ 2 = 28 , find the value of ab . 
Options: a ) 19 , b ) 15 , c ) 10 , d ) 8 , e ) 13
Example Output:
d