Indeed B. What answer choice did you have in mind?

C ..can you xplain d stupid mistake i did

divya23 wrote:C ..can you xplain d stupid mistake i did

Not so stupid - it's actually a pretty strong trap answer choice.

At first I eliminated C because the relative clause beginning with "who" needs to modify what comes directly before it. In B, it correctly modifies "the president, senator, and governor", whereas in C it modifies "cars".

But even if we take the relative clause in C to correctly modify the president, senator and governor, C then makes a slight change in emphasis - by making these people the subject of the setntece, they become the main focus, instead of the original's focus on the fact that they were the first. C, while perhaps grammatically correct, still changes the meaning by implying that the president, sentor etc, were the first political travelers who traveled to washington DC, rather than just the first travelers to travel on modern railroad cars.

thank you so much now i can get it right d next time

i think 2 is the correct answer

Thanks Geva, Even I had a confusion between B and C. Your explanation cleared it.