Correct Answer - Option 4 : (2, 1, 1)
Concept:
Let A(x1, y1, z1) and B(x2, y2, z2) be two points on a 3D plane then mid-point of the line joining the points A and B is given by: \(\rm (\frac{x_{1}+x_{2}}{2}, \frac{y_{1}+y_{2}}{2}, \frac{z_{1}+z_{2}}{2}).\)
Calculation:
Given: R is the mid-point of the line joining the points C(5, 1, 3) and D(- 1, 1, -1).
As we know that, the mid-point of the line joining the points A(x1, y1, z1) and B(x2, y2, z2) is given by: \(\rm (\frac{x_{1}+x_{2}}{2}, \frac{y_{1}+y_{2}}{2}, \frac{z_{1}+z_{2}}{2}).\)
\(\Rightarrow \rm R=(\frac{5-1}{2}, \frac{1+1}{2} ,\frac{3-1}{2} )=(2, 1, 1)\)
Hence, the correct option is 4.