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 20 such machines produce in 4 minutes? Choose the correct choice from the following:
A) 648 B) 1,800 C) 2,700 D) 3,600 E) 64,800
6 machines produce 270 bottles per minute;   1 machine produces 270/6= 
<gadget id="calculator">270/6</gadget>
<output>45</output>
45 bottles per minute;   20 machines produce 45*20= 
<gadget id="calculator">45*20</gadget>
<output>900</output>
900 bottles per minute;   In 4 minutes 10 machines produce 900*4=3,600 bottles.   Answer: 3,600.
<result>D</result>
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 20 such machines produce in 4 minutes?