Concept:For two linear equations in two variables, if a2a1=b2b1, then the lines intersect at exactly one point, giving a unique solution.Explanation:Write the given equations in standard form a1x+b1y+c1=0 and a2x+b2y+c2=0.First equation: x+2y=3 becomes x+2y−3=0.So, a1=1, b1=2, c1=−3.Second equation: 2x+3y=3 becomes 2x+3y−3=0.So, a2=2, b2=3, c2=−3.Now compare the ratios:a2a1=21 and b2b1=32.Since 21=32, the lines are not parallel and intersect at exactly one point.Hence, the system of equations has a unique solution.Answer:Option B: Unique solution.