For functions $f$ and $g$ defined on the set of positive real numbers
$$\begin{aligned}
& ( f \circ g ) ( x ) = f ( x ) \cdot g ( x ) \\
& f ( x ) = 2 x + 3
\end{aligned}$$
Given that, what is the value of $\mathbf { g } ( \mathbf { 1 } )$?
A) 1
B) 2
C) 3
D) 4
E) 5