Given three side lengths, for example, a, b and c, you can form the triangle when

If this property holds, then one triangle you can form. Each next triangle with the same sides lengths will be congruent to the first triangle by SSS postulate.
SSS postulate says: If the three sides of a triangle are congruent to the three sides of another triangle, then the two triangles are congruent.
Answer: 1 triangle, correct option is A.