Answer: D.4/7
Step-by-step explanation:
First, we will find out how many marbles are in the bag.
3 red + 1 blue + 4 yellow - 1 red = 2 red + 1 blue + 4 yellow = 7 marbles
Now, we will put wanted outcomes over possible outcomes.
[tex]\displaystyle \frac{\text{wanted outcomes, yellow marbles}}{\text{possible outcomes, marbles in the bag}} =\frac{4\text{ yellow}}{\text{7 marbles}} =\text{D. 4/7}[/tex]