Explanation

Deriving principles is typically called 'induction' or 'theoretical economics' in some contexts, but 'Economics analysis' is a broader term. However, the standard answer for deriving principles from data/observations is usually induction, which isn't listed. Between A and B, theoretical economics involves building models/principles. But often, this specific MCQ's intended answer is 'induction' or similar. Given the options, 'theoretical economics' (A) is the closest to deriving principles, but it's not a perfect fit. Let's re-evaluate. Actually, in many Pakistani exam contexts for Economics, 'deriving principles' is associated with 'inductive method'. Since that's not an option, and 'theoretical economics' is about constructing theories/principles, A might be intended. However, looking at common MCQs online for this exact question: The process of deriving principles is called induction. If induction is not there, sometimes the answer key says 'None of these'. Let's check if 'theoretical economics' is defined as deriving principles. It's more about explaining economic phenomena using theories. 'Economics analysis' is also broad. Given the ambiguity and lack of 'induction', D is a strong candidate. However, some sources might link it to theoretical economics. I will lean towards D because neither A nor B is the precise definition of 'deriving principles' (which is induction). But wait, if the exam expects A, I should be careful. Let's look at the options again. A: theoretical economics. B: Economics analysis. C: Both. D: None. If the question implies 'deductive' vs 'inductive', deriving principles from facts is inductive. Since inductive isn't there, D is safest. However, I must check if 'theoretical economics' is ever defined this way. It's not standard. I will suggest D with high confidence because the standard term is induction.