A metal alloy machine component is subjected to fluctuating tensile stress from 100 $$\frac{N}{mm^{2}}$$ to 200 $$\frac{N}{mm^{2}}$$. The material has yield and endurance strength of 450 and 200 $$\frac{N}{mm^{2}}$$ respectively. Find the factor of safety of the machine component.

A

$$\frac{5}{6}$$

B

$$\frac{12}{7}$$

C

$$\frac{1}{3}$$

D

$$\frac{6}{5}$$