Quote:
B)
The first political passengers on modern railroad cars were a president, a senator, and a governor, who traveled to Washington, D.C. together on the Liberty Express in 1907.
C)
A president, a senator, and a governor were the first political passengers on modern railroad cars who traveled to Washington, D.C. together on the Liberty Express in 1907.
There are multiple comments saying choice (C) the first political passengers on modern railroad
cars who traveled to Washington is wrong because
who is modifying
cars. This is not true.
We can have a construction like
[noun] [restrictive modifier (like prepositional phrase)]
[Relative Clause]E.g. Let's say we have
Passengers who traveled to Washington, D.C. together.
[Noun] [ Relative Clause ]
Noun - Passengers
Relative Clause - who traveled to Washington, D.C. together. Relative Clause is modifying the Noun.
We can add a restrictive modifier such as prepositional phrase to the noun i.e. Passengers can be more specific - Passengers on railroad cars
Thus
[Passengers on railroad cars][who traveled to Washington, D.C. together] is correct.
[Noun - with prepositional phrase] [ Relative Clause]
Grammatically answer choice C is correct
C) A president, a senator, and a governor were
[
the first political passengers]
(noun) [
on modern railroad cars]
. (prepositional phrase / restrictive modifier) [
who traveled to Washington, D.C. together on the Liberty Express in 1907]
(Relative Clause).