\textbf{121.} In triangle ABC, $BC = 20$, $AH = 12$, and $AB = 12$ units. Line $\Delta$ parallel to BC moves at a constant speed of $0.2$ units per second. The rate of increase of the area of the trapezoid at the moment when the distance between the two parallel lines is 9 units is which of the following?
\textit{[Figure: Triangle ABC with vertex A at top, base BC at bottom, height AH drawn, points D and E on sides AB and AC respectively forming a trapezoid BCED, with H the foot of the altitude on BC]}
\begin{center}
(1) $0.8$ \\[4pt]
(2) $0.9$ \\[4pt]
(3) $1$ \\[4pt]
(4) $1.2$
\end{center}
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