8. For any $\triangle A B C$, let its perimeter, the radius of the circumcircle, and the radius of the incircle be $l, R$, and $r$, respectively. Then,
(A) $l>R+r$;
(B) $l \leqslant R+r$;
(C) $\frac{1}{6}<R+r<6 l$;
(D) None of the relations (A), (B), and (C) are correct.
8. (D)

First, draw a circle with radius $R$. For any positive integer $N$, on this circumference, we can always find three points $A$, $B$, and $C$ that are sufficiently close to each other, such that $AB > R$, $BC > R$, then connect $AC$, thus
$$
l = AB + BC + CA > 2R > R + r.
$$
$\therefore$ (B) is also incorrect.