The correct option is B ∠B+∠A
Given, in ΔABC, BC = 4 cm, AB = 6 cm and AC = 7 cm.
Hence, the ascending order of sides is BC, AB, AC.
In any triangle, the angle opposite to longer side is larger.
∴ Ascending order of angles is ∠A,∠C,∠B.
∴ The sum of the largest and the smallest angle of the given triangle is given by ∠B+∠A.