For a positive number $a$, let the characteristic and mantissa of $\log a$ be $f ( a )$ and $g ( a )$ respectively. Which of the following statements in <Remarks> are true? [3 points]
<Remarks>
\noindent ㄱ. $f ( 2006 ) = 3$\\
ㄴ. $g ( 2 ) + g ( 6 ) = g ( 12 ) + 1$\\
ㄷ. If $f ( a b ) = f ( a ) + f ( b )$, then $g ( a b ) = g ( a ) + g ( b )$.\\
(1) ㄱ\\
(2) ㄱ, ㄴ\\
(3) ㄱ, ㄷ\\
(4) ㄴ, ㄷ\\
(5) ㄱ, ㄴ, ㄷ