Task: Question Answering
Input (English): Problem: a certain maroon paint contains 50 percent blue pigment and 50 percent red pigment by weight . a certain green paint contains 30 percent blue pigment and 70 percent yellow pigment . when these paints are mixed to produce a brown paint , the brown paint contains 40 percent blue pigment . if the brown paint weighs 10 grams , then the red pigment contributes how many grams of that weight ? 
Options: a ) 3 , b ) 3.5 , c ) 2.5 , d ) 4 , e ) 4.5
Output (English): c