ANSWER
B. y=2x+1
EXPLANATION
The graph has a y-intercept of 1.
Let y=mx +b be the equation of the straight line graph.
where b=1 is the y-intercept.
We put this value into the equation to get,
y=mx +1.
Thie point (1,3) must also satisfy this line.
3=m(1)+1
m=3-1
m=2
The equation is
y=2x+1