If $a, b, c$ are positive numbers in G.P. and log $\left(\frac{5 c}{a}\right), \log \left(\frac{3 b}{5 c}\right)$ and $\log \left(\frac{a}{3 b}\right)$ are in A.P. then $a, b, c$
(A) form the sides of an equilateral triangle
(B) form the sides of an isosceles triangle
(C) form the sides of a right angled triangle
(D) can not form the sides of a triangle