Answer : 4. "Martin Cooper"
Explanation :

Martin Cooper, an American engineer and executive, is often regarded as the "Father of the Cellular Phone." He led the team at Motorola that developed the first handheld mobile phone. In 1973, Martin Cooper made the first-ever public call on a handheld mobile phone, known as the Motorola DynaTAC, in New York City. This event marked a significant milestone in the history of telecommunications, as it demonstrated the feasibility of mobile communication beyond traditional landline systems. Martin Cooper's pioneering work laid the foundation for the development and widespread use of mobile phones in the subsequent decades.