A bag is chosen at random from three bags B1,B2 and B3 with probabilities 0.4,0.3 and 0.3 respectively. Bag B1 contains 5 red and 5 blue balls, while bag B2 contains 3 red and 7 blue balls. Bag B3 contains an unknown proportion of red balls. If the overall probability of drawing a red ball is 0.41, what is the probability of drawing a red ball from bag B3?
a) 0.5
b) 0.4
c) 0.6
d) 0.43