If $$a$$ : $$b$$ =$$c$$ : $$d$$ then how many of the following statements are true? 

(i) $$c(a+b)=a(c+d)$$ 

(ii) $$d(a-b)=b(c-d)$$ 

(iii) $$(a^2+b^2)(ac-bd)=(a^2-b^2)(ac+bd)$$ 

(iv) $$\frac{a^2}{b^2}+\frac{c^2}{d^2}=\frac{2ac}{bd}$$

A

1

B

2

C

3

D

All