Which approach to grammar encourages the belief that learning a language is a matter of learning rules ?

The correct option is Deductive.

In language teaching, the deductive approach to grammar is a rule-driven method where learners are first presented with explicit grammatical rules and concepts by the teacher. After understanding these rules, students practice applying them to specific examples and exercises.

This approach directly encourages the belief that learning a language is essentially a matter of memorizing and applying explicit rules (a top-down learning process). In contrast, an inductive approach encourages learners to discover the rules themselves by observing patterns in examples (bottom-up learning).