3. (10 points) As shown in the figure, the number 2015 is written in a grid composed of $1 \times 1$ squares (shaded areas). The boundaries are either horizontal or vertical line segments, or line segments connecting the midpoints of adjacent sides of $1 \times 1$ squares, or the diagonals of $1 \times 1$ squares. The area of the four digits 2015 (shaded areas) in the figure is ( )
A. 47
B. $47 \frac{1}{2}$
C. 48
D. $48 \frac{1}{2}$
【Analysis】Move the shaded small triangles in each number to form small squares, then count how many small squares there are in total, which will give the area of the shaded part.

【Solution】Solution: According to the analysis:
Move the small triangles to fill in the blank areas to complete the whole squares, totaling 47.5, so the area of the shaded part is $47 \frac{1}{2}$;

Therefore, the correct answer is: $B$.