I believe that the answer is b.
Answer:
Jason's speech should be as follows:
"Drug abuse in America's cities <u><em>are</em></u><u> </u>on the rise every day. About 20% more elementary school kids get hooked on narcotics today<u><em>, </em></u> than in the 1960s. So, we can easily see that we've got a big problem. Now<em><u>,</u></em> let's talk about what we can do about it.
Explanation:
In the first sentence Jason uses the incorrect auxiliary verb as the noun referred to is a plural noun and not a singular noun. <em>(Plural Noun = America's cities, therefore the plural auxiliary verb = are)</em>
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In the second sentence, a comma may be added for pause to show the comparison between the present and the past. <em>(... narcotics today</em><u><em>, </em></u><em> than in the 1960s.)</em>
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In the last sentence, a comma may be added to indicate additional information, a pause to offer an effect, or an indication of an instruction to follow. <em>(Now</em><em><u>,</u></em><em> let's talk...)</em>
