The value of $\lambda$ for which the vectors $3\hat i+6\hat j+\hat k$ and $2\hat i+4\hat j+\lambda\hat k$ are parallel is

Question

$$(A)\;\frac{2}{3}\quad(B)\;\frac{3}{2}\quad(C)\;\frac{5}{2}\quad(D)\;\frac{2}{5}$$