1.Let a⃗=2i^−7j^+5k^\vec{a} = 2\hat{i} - 7\hat{j} + 5\hat{k}a=2i^−7j^+5k^, b⃗=i^+k^\vec{b} = \hat{i} + \hat{k}b=i^+k^ and c⃗=i^+2j^−3k^\vec{c} = \hat{i} + 2\hat{j} - 3\hat{k}c=i^+2j^−3k^ be three given vectors. If r⃗\vec{r}r is a vector such that r⃗×a⃗=c⃗×a⃗\vec{r} \times \vec{a} = \vec{c} \times \vec{a}r×a=c×a and r⃗⋅b⃗=0\vec{r} \cdot \vec{b} = 0r⋅b=0, then ∣r⃗∣|\vec{r}|∣r∣ is equal toa.1172\frac{11}{7}\sqrt{2}7112b.117\frac{11}{7}711c.1152\frac{11}{5}\sqrt{2}5112d.9147\frac{\sqrt{914}}{7}7914Login to continueOnly logged in users canattempt or see the solution.