Major Health Studies Try Very Hard to Select a Sample

Major health studies try very hard to select a sample that is representative of the various ethnic groups making up the U.S. population. Here is the breakdown, by ethnicity, of subjects enrolled in a major study of sleep apnea:
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$$\begin{array} { | l | r | } \hline \text { White } & 4821 \\\hline \text { Hispanic } & 277 \\\hline \text { African American } & 510 \\\hline \text { Asian/Pacific } & 88 \\\hline \text { Native American } & 598 \\\hline \text { Total } & 6294 \\\hline\end{array}$$ The known ethnic distribution in the United States, according to census data, is as follows:
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$$\begin{array} { | l | l | } \hline \text { White } & 0.756 \\\hline \text { Hispanic } & 0.091 \\\hline \text { Black } & 0.108 \\\hline \text { Asian/Pacific } & 0.038 \\\hline \text { Native American } & 0.007 \\\hline \text { Total } & 1 \\\hline\end{array}$$ We want to know if the data from the sleep apnea study support the claim that the ethnicity of the subjects fits the ethnic composition of the U.S. population. What is the expected count of Hispanics under the null hypothesis?

A) 277
B) 25.207
C) 572.754
D) 152.72