The best revision to combine sentences two and
three is this one:
<span>
"Let freedom ring” is a phrase which is used many times in Dr.
Martin Luther King Jr’s speech that leads to an exciting conclusion.</span>
<span>
In order to construct correct compound sentences, you should omit words
that contribute to redundancy. </span>
The answer is opinion because, some people might have thought Mckinley was not the smartest president on earth
We need more information! : ) I'll gladly help though!