3. The value of the radical $\sqrt{16 \sqrt{8 \sqrt{4}}}$ is $(\quad)$.
(A) 4
(B) $4 \sqrt{2}$
(C) 8
(D) $8 \sqrt{2}$
(E) 16
3. C.
$$
\sqrt{16 \sqrt{8 \sqrt{4}}}=\sqrt{16 \sqrt{8 \times 2}}=\sqrt{16 \times 4}=8
$$