The principle states that acceptance of a proposal must be the exact mirror image of the proposal itself, meaning the terms accepted must match the terms offered exactly. A offered to sell the chair for Rs. 500, but B wants to buy it for Rs. 400, a different price. Let's check each option against this principle.
Since B's desired price of Rs. 400 does not match A's proposed price of Rs. 500, B's response is a counter-offer rather than an acceptance.
Therefore, the correct answer is B has not accepted the proposal of A.
The principle sets up a simple test: an acceptance only counts as valid if its terms mirror the proposal's terms exactly, with nothing changed. We can express this as a conditional rule: if the terms of the response match the terms of the proposal in every respect, then it is an acceptance; if any term differs, then it is not an acceptance at all. A proposed to sell the chair for Rs. 500, and B wants to buy it for Rs. 400, so the price term does not match. Applying this rule to each option shows which conclusion actually follows.
Since the price term of B's response does not match the price term of A's proposal, the conditional rule for acceptance is not satisfied.
Therefore, the correct answer is B has not accepted the proposal of A.