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'.

[Q]: Problem: find √ ? / 19 = 4 ? 
Options: a ) 76 , b ) 5776 , c ) 304 , d ) 1296 , e ) none
[A]: b


[Q]: Problem: for what value of x between − 8 and 8 , inclusive , is the value of x ^ 2 − 10 x + 16 the greatest ? 
Options: a ) − 8 , b ) − 2 , c ) 0 , d ) 2 , e ) 8
[A]: a


[Q]: Problem: a rower whose speed is 4 km / hr in still water rows to a certain point upstream and back to the starting point in a river which flows at 2 km / hr . what is the rower ' s average speed ( in km / hr ) for the total journey ? 
Options: a ) 6 , b ) 4 , c ) 9 , d ) 3 , e ) 2
[A]:
d