The correct option is D Harishchandra - Concrete Noun; truthfulness - Abstract Noun
Concrete nouns refer to those things or people that can be perceived by any one of our senses such as sight, taste, touch and smell. Abstract nouns denote an idea, a concept, a state of being and other such forms, which cannot be seen or experienced through any of our senses. Harishchandra is the name of a person, a body made of flesh and bone that can be seen and touched, hence it's a concrete noun. Truthfulness is the state of being truthful, hence it's an abstract noun. Option A has the correct forms of these nouns hence it's correct. Option B is incorrect because the former noun is not abstract, it's a person, not a concept or idea and the latter noun is not a physical body, it's a state of being. Similarly, option C is incorrect because Harishchandra is not an abstract noun, and option D is incorrect because truthfulness is not a concrete noun.