To find the correct equation and the number of residents surveyed, we know that two-fifths of the respondents (r) equals 80 residents:
\[ \frac{2}{5} r = 80 \]
To solve for \( r \), we can multiply both sides by the reciprocal of \(\frac{2}{5}\), which is \(\frac{5}{2}\):
\[ r = 80 \cdot \frac{5}{2} \]
Calculating that:
\[ r = 80 \cdot 2.5 = 200 \]
So, the equation that represents the number of residents surveyed is:
\[ \frac{2}{5} r = 80 \]
And the total number of residents surveyed is:
\[ 200 \text{ residents.} \]
Therefore, the correct response is:
\(\frac{2}{5} r = 80; 200 \text{ residents were surveyed.}\)