The Mehrauli Pillar, located in the complex of Qutub Minar, is primarily famous for its excellent quality steel. The pillar has stood the test of time and has not shown any signs of corrosion or rust despite being exposed to the elements for centuries. This has led to its reputation for housing steel of exceptional quality. Option 1, proverbial height, is not the primary feature of the pillar. Option 2, skilful stone cutting, is not applicable to the Mehrauli Pillar as it is made of iron, not stone. Option 4, a statue of Buddha on top, is not present on the Mehrauli Pillar. Therefore, the correct answer is 3.