If a triangle has at least two congruent sides, it is an isosceles triangle. An equilateral triangle has three congruent sides.Which of the following is valid based on deductive reasoning? A. An isosceles triangle is an equilateral triangle. B. An equilateral triangle is an isosceles triangle. C. An isosceles triangle has three congruent sides. D. An equilateral triangle has two congruent sides.