Which among the following gives more freedom to the learner to interact ?

Concept: Teaching methods differ in the DIRECTION of communication they set up. A one-way (expository or mass-delivery) method carries a message from a single fixed source to many receivers, so the content and its pace are settled before the learner ever meets them. A two-way (learner-centred) method distributes the speaking turns among the participants themselves, so a learner can question, answer, disagree and redirect the exchange while it is happening. Freedom to interact is therefore greatest where the channel is two-way AND the group is small enough that every learner actually gets a turn.

Application: Apply that continuum to the four methods offered. A small group discussion places a handful of learners around a shared question: every member is both a sender and a receiver, the small size guarantees that speaking time is available to each one, and the teacher functions as a facilitator rather than the sole source. Both conditions of the concept are met, so "Small group discussion" gives the learner the most freedom to interact.

Cross-check — the same four methods on one criterion:

Result: The criterion that separates the four is the live return channel. Ranked by the learner's own talk-time the order runs small group discussion, then expert lecture, then film, then country-wide TV broadcast. Of the four, only a small group discussion keeps a two-way channel open to every participant for the whole session, which is exactly the condition the concept sets out.