Task: Question Answering
Input (English): Problem: in a renowned city , the average birth rate is 4 people every two seconds and the death rate is 2 people every two seconds . estimate the size of the population net increase that occurs in one day . 
Options: a ) 86,400 , b ) 172,800 , c ) 468,830 , d ) 338,200 , e ) 259,200
Output (English): a