In △ABC, we have \angle C \equal{} 3 \angle A, a \equal{} 27, and c \equal{} 48. What is b?[asy]size(200);
defaultpen(linewidth(0.7)+fontsize(10));
pair A=origin, B=(14,0), C=(10,6);
draw(A--B--C--cycle);
label("A", A, SW);
label("B", B, SE);
label("C", C, N);
label("a", B--C, dir(B--C)*dir(-90));
label("b", A--C, dir(C--A)*dir(-90));
label("c", A--B, dir(A--B)*dir(-90));
[/asy]<spanclass=′latex−bold′>(A)</span>33<spanclass=′latex−bold′>(B)</span>35<spanclass=′latex−bold′>(C)</span>37<spanclass=′latex−bold′>(D)</span>39<spanclass=′latex−bold′>(E)</span>not uniquely determined