Task: Question Answering
Input (English): Problem: a box contains 10 tablets of medicine a and 10 tablets of medicine b . what is the least number of tablets that should be taken from the box to ensure that at least two tablets of each kind are among the extracted . 
Options: a ) 12 , b ) 15 , c ) 17 , d ) 19 , e ) 21
Output (English): a