The value of $4\left(\lambda_{1}+\lambda_{2}+\lambda_{3}\right)$ where, $\lambda_{1,} \lambda_{2}, \lambda_{3}$ are the values of $\lambda$ for which the system of equations $(3-\lambda) x+y+$ $4 \mathrm{z}=0 ;(2-\lambda) \mathrm{y}+6 \mathrm{z}=0 ;(5-\lambda) \mathrm{z}=0$ has non trivial solutions, is
(a) 40
(b) 10
(c) 4
(d) 400