Key PointsIntension and extension, in logic, are correlative words that indicate the reference of a term or concept. “intension” indicates the internal content of a term or concept that constitutes its formal definition, an “extension” indicates its range of applicability by naming the particular objects that it denotes. Important Points When we define a term according to its intension, we define it according to its characteristics. “Cat,” is a furry, four-legged, meowing creature. When we define a term according to its extension, we define it according to the class or collection of things to which the term refers. “Cat” is a feline animal. We can also talk about increasing or decreasing intension. We can also talk about increasing or decreasing extension. Notice the inverse relations: a series of increasing intension is also a series of decreasing extension: biodegradable, edible, vegetable, broccoli. A series of increasing extension is also a series of decreasing intension: broccoli, vegetable, edible, biodegradable. In some cases, an intensional definition will make for a clearer sentence than an extensional definition, and vice versa. Therefore in the given example following statements are true with reference to this series that it is in order of increasing intention and it is in order of decreasing extension. Thus Only (A) and (D) is correct.