Final answer:
The limited access zone should be the height of the wall plus four feet, so for a 12 feet high wall, it should be 16 feet, not 14 feet.
Step-by-step explanation:
The correct answer to why the supervisor may have pulled the student aside is that the limited access zone is supposed to be the height of the wall plus four feet, so 16 feet rather than 14 feet. Option 4 is the correct answer. Therefore, the limited access zone you have created is insufficient for the height of the masonry wall being built.