(a) consistent with unique solution.
The two lines intersect at a single point, giving exactly one solution. Hence the pair is consistent with a unique solution.
Source: Chapter 3, Section 3.2 – Graphical Method of Solution of a Pair of Linear Equations
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When two lines intersect at one point, the pair of linear equations has exactly one (unique) solution → consistent. Examiners expect you to recall: intersecting lines = consistent + unique solution; coincident lines = consistent + infinitely many solutions; parallel lines = inconsistent. Option (d) is a distractor — intersecting lines already meet, so no "extension" is needed.