7. (10 points) Divide a large triangle into 36 small triangles, and color some of the small triangles red and others blue, ensuring that two triangles sharing a common edge have different colors. If there are more red triangles than blue ones, how many more are there?
A. 1
B. 4
C. 6
D. 7
【Answer】Solution: According to the analysis, if we color according to the requirements of the problem, there is only 1 way to color, as shown in the figure: the number of red is more than the number of blue: $(1+2+3+4+5+6)-(1+2+3+4+5)=6$.

Therefore, the correct choice is: $C$.