A car travels 225 km in 4.5 hours. How long will it take to travel 150 km at the same speed?

The formula for speed is:

$$\text{Speed} = \frac{\text{Distance}}{\text{Time}}$$

Given:
Distance ($D_1$) = 225 km
Time ($T_1$) = 4.5 hrs

Substitute these values into the formula:

$$S = \frac{225 \text{ km}}{4.5 \text{ hrs}}$$ $$S = 50 \text{ km/hr}$$

Now that we have the constant speed, we can find the time ($T_2$) it takes to run a new distance ($D_2$) of 150 km.
The formula for time is:

$$\text{Time} = \frac{\text{Distance}}{\text{Speed}}$$

Given:
Distance ($D_2$) = 150 km
Speed ($S$) = 50 km/hr (calculated in Step 1)

Substitute these values into the formula:

$$T_2 = \frac{150 \text{ km}}{50 \text{ km/hr}}$$ $$T_2 = 3 \text{ hrs}$$

The time it will take to run 150 km is 3 hours.

Comparing this with the given options:
A. 2 hrs
B. 1 hr
C. 3 hrs
D. 4 hrs

The calculated time matches option C.

The final answer is $\boxed{\text{C. 3 hrs}}$.