The correct option is D Equilateral Triangle
According to question,
BO is perpendicular to AC and AO = OC
∵ BO is cutting the base into half and is also perpendicular to it
∴ BO is acting both as an altitude and median.
An altitude acts as a median only in an Equilateral or Isosceles triangle with AB and BC being equal in length.
For the triangle ABC,
Sum of all angles = 180o
Or, ∠A + ∠B + ∠C = 180o
Or, ∠A + ∠C + 60o = 180
Or, 2∠A = 180o - 60o (∵ angles opposite to equal sides are equal)
Or, ∠A = 120o2 = 60o
∵ ∠A = ∠B = ∠C = 60o
∴ The above triangle is an Equilateral triangle