The function $f$ is defined by $f(x)=p(3^x+3^q)$, where $p$ and $q$ are integer constants and $0<p<q$. The functions $g$ and $h$ are equivalent to function $f$, where $k$ and $m$ are constants. Which of the following equations displays the $y$-coordinate of the $y$-intercept of the graph of $y=f(x)$ in the $xy$-plane as a constant or coefficient?
I. $g(x)=p(3^x+k)$
II. $h(x)=p(3{)}^x+m$