Task: Question Answering
Input (English): Problem: a certain maroon paint contains 70 percent blue pigment and 30 percent red pigment by weight . a certain green paint contains 10 percent blue pigment and 90 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 ) 1.5 , b ) 2 , c ) 2.5 , d ) 3 , e ) 3.5
Output (English): a