The sides of a triangle are of length a, b, c and medians of that triangle are of length x,y,z. Which one of the following is true?

a) 2(a2+b2+c2) = 3(x2+y2+z2)
b) 3(a2+b2+c2) = 4(x2+y2+z2)
c) 3(a2+b2+c2) = 5(x2+y2+z2)
d) 4(a2+b2+c2) = 5(x2+y2+z2)
e) 5(a2+b2+c2) = 4(x2+y2+z2)

OE B