Answer:
d. All of the above are included in the category, "land."
Step-by-step explanation:
In economics, when we talk about Land, Labor and Capital we talk about all the resources available. For example capital can include money and machinery needed for production and labor can involve all human resources.
Similarly in land all natural resources are considered. These include forests, bauxite deposits and pools of crude oil. All of these are "Land".
Hope that helps.