Select the correct answer from each drop-down menu.

Bart runs a food truck in front of a multi-story office building. He wants to know which type of sandwiches his customers prefer, grilled or plain. He randomly surveyed a few of his friends who have eaten at his food truck and recorded the results.

\begin{tabular}{|c|c|}
\hline Friends Preferring Grilled Sandwiches & Friends Preferring Plain Sandwiches \\
\hline 15 & 5 \\
\hline
\end{tabular}

In this case, the population consists of [tex]$\square$[/tex] and the sample consists of [tex]$\square$[/tex]. Based on the results, it can be concluded that [tex]$\square$[/tex]. The results would have been more accurate if Bart had surveyed [tex]$\square$[/tex].