Two particles of masses 1 kg and 3 kg have velocities $(2 \hat i-3 \hat j+4 \hat k)ms^{-1}$ and $(4 \hat {i}+2 \hat j+\hat k)ms^{-1}$ at a given instant of time. The velocity of the center of mass is

Question

$$\begin {array} {1 1} (a)\;3.5 \hat{i}+2.25 \hat{j}+1.75 \hat {k} \;m/s\\ (b)\;3.5 \hat{i}-2.25 \hat{j}+1.75 \hat {k} \;m/s \\ (c)\;2.5 \hat{i}+2.25 \hat{j}+1.75 \hat {k} \;m/s \\(d)\;3.5 \hat{i}+0.75 \hat{j}+1.75 \hat {k} \;m/s  \end {array}$$