The equation of the plane in normal form passing through the point $A(\vec{a})$, parallel to a vector $\vec{b}$ and containing a vector $\vec{c}$ is

• A
  $\vec{r} \cdot \frac{\vec{c} \times \vec{a}}{|\vec{c} \times \vec{a}|} = \left|\frac{\vec{a} \times \vec{b}}{\vec{a} \times \vec{c}}\right|$
• B
  $\vec{r} \cdot \frac{\vec{a} \times \vec{b}}{|\vec{a} \times \vec{b}|} = \frac{[\vec{a} \vec{b} \vec{c}]}{|\vec{b} \times \vec{c}|}$
• C
  $\vec{r} \cdot \frac{\vec{b} \times \vec{c}}{|\vec{b} \times \vec{c}|} = \frac{[\vec{a} \vec{b} \vec{c}]}{|\vec{b} \times \vec{c}|}$
• D
  $\vec{r} \cdot [\vec{a} \vec{b} \vec{c}] \vec{a} = \frac{|\vec{b} \times \vec{c}|}{|\vec{a} \times \vec{c}|}$