Respuesta :

B,C, and D could all be triangles because when making a triangle the sum of two sides has to be bigger than the number of the third side. Sorry for the wierd wording, haven't slept in 3 days.
For a triangle to be formed the sum of the 2 shorter sides must be  greater than the longest side.
Or the sides can be all the same as in C.  

Answer is C.