I believe it's B: To persuade his audience to trust him.
Answer:
You didn't give me any context but I'd go with C
Explanation:
<span>Words of the same root with different affixes are well
thought-out different words, so in that regard it would follow that there would
be more words. But if you mean there might be a capability to change an
existing word simply and clearly put off or negate people inventing entirely
new words, root and all? In that circumstance, especially considering each
modification of a root is in theory a separate word, there would be no much
impact; all words have to start from somewhere.</span>