A dilation represents a transformation

, centered at point O with a scale factor of k, which cannot be zero. This transformation keeps O fixed while transforming any other point P into its image P'. Points O, P, and P' are collinear.
In a dilation of

, the scale factor

maps the original figure to its transformed image in such a way that the distances from O to points of the image are half the distances from O to the original figure. Consequently, the image's size is also half that of the original figure.
Thus, <span>If

represents the dilation of △ABC, then the properties of the image △A'B'C'</span> are:
<span>AB is parallel to A'B'.

The distance from A' to the origin is half that from A to the origin.</span>
Because each share was originally purchased at 20 1/4, the gain per share when the price rises to 25 1/4 is (25 1/4 - 20 1/4) = $5.00. Selling 30 shares therefore yields a total profit of (30 x 5) = $150.00. Thus, the correct choice is C<span>.</span>