The correct option is C Abstract Noun / Uncountable Noun
Abstract nouns denote a quality, an idea or state, as opposed to concrete objects. Most abstract nouns are uncountable. The italicized word 'honesty' refers to the state of being honest, hence it's an abstract as well as uncountable noun and option A is thus, correct. Option B is incorrect because honesty cannot be counted, it's a state of being which is abstract in nature and cannot be measured. Option C is incorrect because concrete nouns refer to physical objects whereas honesty is not a physical object. Option D is incorrect because honesty is not a physical object, nor can it be counted.