If\[x=\frac{1}{3}y\] and \[y=\frac{1}{2} z\] then \[x:y:z=\]?

• A. \[3:2:1\]                       
• B. \[1:2:3\]
• C. \[1:3:6\]          
• D. \[2:4:6\]