If Stacy can paint \( \frac{3}{4} \) of the bedroom in 3 hours, we can first determine her painting rate.
At this rate, she paints:
\[ \frac{3}{4} \text{ of the room in } 3 \text{ hours} \]
To find out how long it takes her to paint the entire room (1 whole room), we can set up a proportion:
\[ \text{Time to paint 1 room} = \frac{3 \text{ hours}}{\frac{3}{4}} = 3 \text{ hours} \div \frac{3}{4} = 3 \text{ hours} \times \frac{4}{3} = 4 \text{ hours} \]
So, it will take Stacy 4 hours to paint the entire room.
The correct answer is 4 hours.