When loading and securing a boulder, it should be `_________`.

A All of these are requirements.

explanation

Requirements Place each boulder on the vehicle with its flattest and/or largest side down. Support each boulder on at least two pieces of hardwood blocking (at least 10 cm x 10 cm (4 x 4 in) that extend the full width of the boulder. Place hardwood blocking pieces as symmetrically as possible under the boulder so they support at least 3/4 of the length of the boulder.