how to plot contour between three irregularly spaced matrices??

I have three matrices A,B and C having same size 40*40. I want to plot a contour of C(40*40) taking A(40*40) as x axis and B(40*40) as y axis and columns and rows of A or B are not are strictly increasing or strictly decreasing. Is it the correct way to plot by the following code ? Please help.

contourf (A,B,C);