Task: Question Answering
Input (English): Problem: running at the same constant rate , 6 identical machines can produce a total of 270 bottles per minute . at this rate , how many bottles could 12 such machines produce in 4 minutes ? 
Options: a ) 648 , b ) 1800 , c ) 2700 , d ) 2160 , e ) none of these
Output (English): d