Answer
Answer B
Work Step by Step
$$\log(x+3)+\log x=1\\\log(x(x+3))=1\\\log(x^2+3x)=1\\x^2+3x=10\\x^2=3x-10=0\\(x+5)(x-2)=0\\x=-5 \lor x=2$$
Since $x=-5$ is not defined for the original equation, the only solution here is $x=2.
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Hence, the correct answer is $B$.
