The function $f$ is defined by $f(x)=P(R^x+R^Q)$, where $P$ and $Q$ are positive integer constants and $P<Q$. The functions $g$ and $h$ are equivalent to function $f$, where $K$ and $M$ are constants.
$g(x)=P\cdot R^x+K$
$h(x)=P(R^x+M)$
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?