Which of these is correct for the direction of the normal vectors to faces?

• A. <a href="https://www.sanfoundry.com/wp-content/uploads/2019/10/computational-fluid-dynamics-questions-answers-unstructured-grids-fvm-q6a.png"><img alt="The direction of the normal vectors to faces - option a" class="alignnone size-full wp-image-251153" height="134" src="https://www.sanfoundry.com/wp-content/uploads/2019/10/computational-fluid-dynamics-questions-answers-unstructured-grids-fvm-q6a.png" width="141"/></a>
• B. <a href="https://www.sanfoundry.com/wp-content/uploads/2019/10/computational-fluid-dynamics-questions-answers-unstructured-grids-fvm-q6b.png"><img alt="The direction of the normal vectors to faces - option b" class="alignnone size-full wp-image-251154" height="133" src="https://www.sanfoundry.com/wp-content/uploads/2019/10/computational-fluid-dynamics-questions-answers-unstructured-grids-fvm-q6b.png" width="153"/></a>
• C. <a href="https://www.sanfoundry.com/wp-content/uploads/2019/10/computational-fluid-dynamics-questions-answers-unstructured-grids-fvm-q6c.png"><img alt="The direction of the normal vectors to faces - option c" class="alignnone size-full wp-image-251155" height="134" src="https://www.sanfoundry.com/wp-content/uploads/2019/10/computational-fluid-dynamics-questions-answers-unstructured-grids-fvm-q6c.png" width="142"/></a>
• D. <a href="https://www.sanfoundry.com/wp-content/uploads/2019/10/computational-fluid-dynamics-questions-answers-unstructured-grids-fvm-q6d.png"><img alt="The direction of the normal vectors to faces - option d" class="alignnone size-full wp-image-251156" height="134" src="https://www.sanfoundry.com/wp-content/uploads/2019/10/computational-fluid-dynamics-questions-answers-unstructured-grids-fvm-q6d.png" width="146"/></a>