Concept:The equation of a straight line is y=mx+c, where m is the slope and c is the y-intercept.Explanation:From the graph, the line passes through the points (1,1) and (0,3).The slope is calculated as m=x2−x1y2−y1.Using (x1,y1)=(1,1) and (x2,y2)=(0,3):m=0−13−1=−12=−2.Now use the general point (x,y) and a known point, say (1,1):x−1y−1=−2.Rewrite −2 as 1−2, then cross multiply:y−1=−2(x−1).Simplify: y−1=−2x+2.Add 1 to both sides: y=−2x+3.This matches the line's y-intercept of 3, confirming the equation.Answer:y=−2x+3, which is Option A.