4. Given $a+b+c=10, a^{2}+b^{2}+c^{2}=38$, $a^{a}+b^{3}+c^{8}=160$. Then, the value of $a b c$ is ( ).
(A) 24.
(B) 30.
(C) 36.
(D) 42.
B

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