उत्तर : 3. "जोसेफ आस्पदिन"
व्याख्या :

Joseph Aspdin, an English bricklayer and mason, is credited with the invention of modern Portland cement. In 1824, Aspdin patented a process for producing a hydraulic cement by burning finely ground limestone and clay together. The resulting product, which he named "Portland cement" due to its resemblance to Portland stone, became a key component in the construction industry.

Aspdin's innovation marked a significant development in the production of cement, and Portland cement remains the most widely used type of cement in the world for various construction applications.