Explanation:

All right, let's roll up our sleeves on this one. Start with the basics:

- Car B goes at 50 km/hr for 7.5 hours.

- So, distance for B = 50 × 7.5 = 375 km.

- Car A goes 33?% more than B.

- That means ? more. 33?% of 375 = 125, so Car A = 375 + 125 = 500 km.

- Car C goes 400 km at 20% less speed than B.

- 20% less than 50 km/hr: 50 × 0.8 = 40 km/hr.

Now the main bit—B starts 2 hours after C, and both go in the same direction.

- In 2 hours, C covers 2 × 40 = 80 km.

- After those 2 hours, B starts chasing:

- The speed difference: 50 km/hr (B) – 40 km/hr (C) = 10 km/hr.

- Gap to close: 80 km.

- Time to close gap: 80 km / 10 km/hr = 8 hours.

So, after 8 hours, Car B catches up to Car C. That’s option 4.

? Option: 4 – 8 hours is the right answer.