SAT Right triangles Question

The function $f$ is defined by $f(x)=a(3.1^x+3.1^b)$ , where $a$ and $b$ are integer constants and $0<a<b$ . 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. $g(x)=a(3.1^x+k)$ II. $h(x)=a(3.1{)}^x+m$