Blue: $(50 + 5 - 4) \div 3 = 17$  Red: $17 + 4 = 21$ 
Edwin has three flowers, one red, one blue and one yellow. They have $50$ petals in total. The blue flower has $4$ petals less than the red one and $5$ petals more than the yellow one. How many petals does the red flower have? 
A. $$12$$ 
B. $$13$$ 
C. $$17$$ 
D. $$21$$ 
E. $$22$$ 