Employers must guard employees from three types of hazards. these include a floor that is large enough for a person to fall into, a floor hole that is large enough and for small items to fall into, and a wall opening that is large enough for a person to fall through and is at least 4 feet above the ground

These include a floor opening that is large enough for a person to fall into, a floor hole that is large enough and deep enough for small items to fall...

Explanation:

Employers are required by law to promote and establish a safe environment that reduces the risk of accidents for their workers. Workers, in turn, must be committed to safety by using personal safety equipment and avoiding hazardous situations. Employers' obligation to maintain a safe environment includes a floor opening that is large enough for a person to fall into, a floor hole that is large enough and deep enough for small items to fall into, and a wall opening that is large enough for a person to fall through and is at least 4 feet above the ground

i say that the answer is 'd'