Let \(\rm \overrightarrow a = 2\widehat i - 3\widehat j + 4\widehat k\) and \(\rm \overrightarrow b = 7\widehat i + \widehat j - 6 \widehat k\).
If \(\rm \overrightarrow r \times \overrightarrow a = \overrightarrow r \times \overrightarrow b ,\overrightarrow r \cdot (\widehat i + 2\widehat j + \widehat k) = - 3\), then \(\rm \overrightarrow r \cdot (2\widehat i - 3\widehat j + \widehat k)\) is equal to :
1
8
2
10
3
12
4
13