Task: SWRL-based Rule Reasoning (ontology: Earth_Environment/EnvironmentOntology)

Suppose an individual ?x satisfies: cyclic tetrapyrrole anion(?x). Which conclusion is one valid inferred conclusion?

A. carboxylic acid anion(?x)
B. carbon oxoanion(?x)
C. organic anion(?x)
D. organic cation(?x)

Answer: organic anion(?x)