The second alternative is correct (B).
"Gold in California ignited interest in a railroad to reach the West. However, Americans disagreed on where to build the railroad."
The use of the conjunction "however" in this context connects the two sentences with a contraposition, giving the exact meaning for the continuity of the text. In this way, it became clear that there was a need to build a railroad, but there was no unity among Americans about where to build the railroad.
<span>b. antonyms,
</span><span>synonyms mean the same, these two words are not the same.</span>
