दो समतल दर्पण \(M _{1}\) तथा \(M _{2}\) चित्रानुसार एक दूसरे के लम्बवत हैं। एक बिन्दु स्त्रोत ' \(P\) ' दर्पण \(M _{1}\) तथा \(M _{2}\) से क्रमशः ' \(a\) ' और ' \(2 a\) ' मीटर दूर रखे है। इस प्रकार बने प्रतिबिम्बों के बीच न्यूनतम दूरी है। \((\sqrt{5}=2.3)\)

Apply the relevant identity from the chapter and substitute the values established in the previous step, keeping the original constraint in view.

Use the simplified expression to isolate the unknown, then plug the result back into the question setup to confirm the working is internally consistent.

Cross-check against a boundary or limiting case. Both the dimensional balance and the qualitative behaviour at the extreme should agree with the candidate answer.

Combine the steps above to identify the correct option. The remaining choices each fail at least one of the consistency, dimensional, or boundary checks.