To analyze the polynomial \( A(l) = 12l^2 - 3l \), we note that it represents the area of a rectangle, where \( l \) is the length of the rectangle. According to the problem statement, the width \( w \) of the rectangle is described as "3 less than half its length," which can be expressed as:
\[ w = \frac{1}{2}l - 3 \]
The area \( A \) of a rectangle is given by:
\[ A = \text{length} \times \text{width} = l \times w \]
Substituting the expression for \( w \):
\[ A = l \left( \frac{1}{2}l - 3 \right) = \frac{1}{2}l^2 - 3l \]
It seems there might have been a discrepancy in the polynomial provided, as multiplying out the widths results in a different coefficient compared to the given polynomial \( A(l) = 12l^2 - 3l \). Let's assume \( A(l) \) is supposed to represent a direct relationship with respect to \( l \) regardless of the constant.
The quantity that directly corresponds to \( A(l) \) when evaluated concerning length and width is:
- Quantity #1: length of the rectangle and width of the rectangle.
Thus, the most appropriate choice from the perspectives described is Quantity #1.