This type of belief is called Naturalism. It is a philosophical belief in realism/reality, that only what we can physically see and explain is real and true. A modern view point would be that if something cannot be proved scientifically then it does not exist and that is naturalism.
I believe C is the answer.
Derived demand<span> is a </span>term<span> used in the economic analysis that describes the </span>demand placed<span> on one good or service as a result of changes in the price for some other related good or service. It is a </span>demand<span> for some physical or intangible thing where a market exists for both related goods and services in question.</span>