$\begin{array}{1 1} (a)\:\overrightarrow r=(\hat i+2\hat j-5\hat k)+\lambda(\hat i+2\hat j+3\hat k) & (b)\: \overrightarrow r=(\hat i+2\hat j+3\hat k)+\lambda(\hat i+2\hat j-5\hat k) \\ (c)\:\overrightarrow r=(-\hat i-2\hat j+5\hat k)+\lambda(\hat i+2\hat j+3\hat k) & (d)\:\overrightarrow r=(-\hat i-2\hat j-3\hat k)+\lambda(\hat i+2\hat j-5\hat k) \end{array} $