Explanation:

Certainly! Let's break down the solution step by step:

- Speed of Train: It is given as 144 km/h. Convert this speed into meters per second:

$$

144 \times \frac{1000}{3600} = 40 \text{ m/s}

$$

- Time Taken: The train crosses the platform in 30 seconds.

- Total Distance Covered: In these 30 seconds, at a speed of 40 m/s, the train covers:

$$

40 \times 30 = 1200 \text{ meters}

$$

- Distance Calculation: This total distance includes the length of the train plus the platform:

$$

\text{Length of the Train} + 100 = 1200 \text{ meters}

$$

- Length of Train:

$$

\text{Length of Train} = 1200 - 100 = 1100 \text{ meters} = 1.1 \text{ km}

$$

- Correct Answer: Option 3

- 1.1 km